diff --git a/2021/d18/ex1/ex1.py b/2021/d18/ex1/ex1.py
deleted file mode 100755
index 7a02746..0000000
--- a/2021/d18/ex1/ex1.py
+++ /dev/null
@@ -1,208 +0,0 @@
-#!/usr/bin/env python
-
-import functools
-import itertools
-import sys
-from dataclasses import dataclass
-from typing import Iterator, List, Optional, Tuple
-
-
-@dataclass
-class Tree:
-    parent: Optional["Pair"]
-
-
-@dataclass
-class Pair(Tree):
-    left: Tree
-    right: Tree
-
-
-@dataclass
-class Num(Tree):
-    val: int
-
-
-# True means left, False means right
-Path = List[bool]
-
-
-def solve(input: List[str]) -> int:
-    def make_pair(left: Tree, right: Tree, parent: Optional[Pair] = None) -> Pair:
-        pair = Pair(parent=parent, left=left, right=right)
-        pair.left.parent = pair
-        pair.right.parent = pair
-        return pair
-
-    def make_num(val: int, parent: Optional[Pair] = None) -> Num:
-        return Num(parent=parent, val=val)
-
-    # FIXME: remove this
-    def debug(tree: Tree) -> str:
-        if isinstance(tree, Pair):
-            return f"[{debug(tree.left)},{debug(tree.right)}]"
-        assert isinstance(tree, Num)
-        return str(tree.val)
-
-    def parse() -> List[Tree]:
-        def parse_snailfish_number(line: str) -> Tree:
-            def parse_index(input: str, index: int = 0) -> Tuple[int, Tree]:
-                if input[index] == "[":
-                    left_index, left = parse_index(input, index + 1)
-                    assert input[left_index] == ","  # Sanity check
-                    right_index, right = parse_index(input, left_index + 1)
-                    assert input[right_index] == "]"  # Sanity check
-                    return right_index + 1, make_pair(left, right)
-                res = 0
-                for i in itertools.count(index):
-                    if i < len(input) and input[i] in set(str(i) for i in range(10)):
-                        res = res * 10 + int(input[i])
-                    else:
-                        return i, make_num(res)
-                assert False  # Sanity check
-
-            __, res = parse_index(line)
-            return res
-
-        return [parse_snailfish_number(line) for line in input]
-
-    def explosion_path(number: Tree) -> Optional[Path]:
-        def dfs(number: Pair, path: Path = []) -> Optional[Path]:
-            if (
-                len(path) >= 4
-                and isinstance(number.left, Num)
-                and isinstance(number.right, Num)
-            ):
-                return path
-            if isinstance(number.left, Pair):
-                left_path = dfs(number.left, path + [True])
-                if left_path is not None:
-                    return left_path
-            if isinstance(number.right, Pair):
-                right_path = dfs(number.right, path + [False])
-                if right_path is not None:
-                    return right_path
-            return None
-
-        assert isinstance(number, Pair)  # Sanity check
-        return dfs(number)
-
-    def split_path(number: Tree) -> Optional[Path]:
-        def dfs(number: Pair, path: Path = []) -> Optional[Path]:
-            if isinstance(number.left, Num):
-                if number.left.val >= 10:
-                    return path + [True]
-            else:
-                assert isinstance(number.left, Pair)  # Sanity check
-                if (left_path := dfs(number.left, path + [True])) is not None:
-                    return left_path
-            if isinstance(number.right, Num):
-                if number.right.val >= 10:
-                    return path + [False]
-            else:
-                assert isinstance(number.right, Pair)  # Sanity check
-                if (right_path := dfs(number.right, path + [False])) is not None:
-                    return right_path
-            return None
-
-        assert isinstance(number, Pair)  # Sanity check
-        return dfs(number)
-
-    def explode(number: Tree, path: Path) -> Tree:
-        def walk(number: Tree, reverse: bool) -> Iterator[Tree]:
-            if isinstance(number, Num):
-                yield number
-            else:
-                assert isinstance(number, Pair)  # Sanity check
-                first, second = (
-                    (number.right, number.left)
-                    if reverse
-                    else (number.left, number.right)
-                )
-                yield from walk(first, reverse)
-                yield number
-                yield from walk(second, reverse)
-
-        def next_num(number: Tree, reverse: bool) -> Optional[Num]:
-            if number.parent is None:
-                return None
-            sibling = number.parent.left if reverse else number.parent.right
-            if number is sibling:
-                return next_num(number.parent, reverse)
-            for node in walk(sibling, reverse=reverse):
-                if isinstance(node, Num):
-                    return node
-            return None
-
-        assert isinstance(number, Pair)  # Sanity check
-
-        if len(path) == 0:
-            p, n = next_num(number, reverse=True), next_num(number, reverse=False)
-            if p is not None:
-                assert isinstance(number.left, Num)  # Safety check
-                p.val += number.left.val
-            if n is not None:
-                assert isinstance(number.right, Num)  # Safety check
-                n.val += number.right.val
-            return make_num(0)
-
-        parent, left, right = number.parent, number.left, number.right
-        if path[0]:
-            left = explode(number.left, path[1:])
-        else:
-            right = explode(number.right, path[1:])
-
-        return make_pair(parent=parent, left=left, right=right)
-
-    def split(number: Tree, path: Path) -> Tree:
-        def split_int(num: int, parent: Optional[Pair]) -> Tree:
-            assert num >= 0  # Sanity check
-            left = num // 2
-            right = num - left
-            res = make_pair(left=make_num(left), right=make_num(right), parent=parent)
-            return res
-
-        if len(path) == 0:
-            assert isinstance(number, Num)  # Sanity check
-            return split_int(number.val, number.parent)
-
-        assert isinstance(number, Pair)  # Sanity check
-
-        parent, left, right = number.parent, number.left, number.right
-        if path[0]:
-            left = split(number.left, path[1:])
-        else:
-            right = split(number.right, path[1:])
-
-        return make_pair(parent=parent, left=left, right=right)
-
-    def reduce(number: Tree) -> Tree:
-        path = explosion_path(number)
-        if path is not None:
-            return reduce(explode(number, path))
-        path = split_path(number)
-        if path is not None:
-            return reduce(split(number, path))
-        return number
-
-    def add(left: Tree, right: Tree) -> Tree:
-        return reduce(make_pair(left=left, right=right))
-
-    def magnitude(number: Tree) -> int:
-        if isinstance(number, Num):
-            return number.val
-        assert isinstance(number, Pair)  # Safety check
-        return 3 * magnitude(number.left) + 2 * magnitude(number.right)
-
-    numbers = parse()
-    result = functools.reduce(add, numbers)
-    return magnitude(result)
-
-
-def main() -> None:
-    input = [line.strip() for line in sys.stdin.readlines()]
-    print(solve(input))
-
-
-if __name__ == "__main__":
-    main()
diff --git a/2021/d18/ex1/input b/2021/d18/ex1/input
deleted file mode 100644
index 1dd0bc9..0000000
--- a/2021/d18/ex1/input
+++ /dev/null
@@ -1,100 +0,0 @@
-[[3,[8,[2,1]]],[[[0,6],[0,2]],3]]
-[[[1,[8,5]],[[3,9],0]],2]
-[5,[[5,[3,8]],[7,4]]]
-[1,[[[0,4],[8,5]],6]]
-[[[1,[0,3]],2],[2,[0,[7,9]]]]
-[[[4,[4,4]],[[7,2],[7,1]]],9]
-[5,[4,4]]
-[[0,[[2,6],[8,9]]],[[4,5],2]]
-[[[8,2],0],3]
-[[9,0],[3,3]]
-[[[[5,2],2],5],5]
-[[[1,6],[[0,4],[7,7]]],[[1,4],[[6,5],5]]]
-[[[[4,1],[4,1]],[2,[5,5]]],[1,[0,[0,6]]]]
-[[[[1,5],1],[8,4]],[9,[3,4]]]
-[[1,[3,3]],[[[7,4],[8,1]],2]]
-[3,[[[2,1],4],[5,4]]]
-[6,[[0,[1,9]],[[4,0],8]]]
-[5,[7,[7,[8,8]]]]
-[[[[6,2],[5,8]],[5,[3,1]]],[[7,9],[[2,0],6]]]
-[[[7,[7,9]],[5,7]],[[[9,3],[6,9]],[[1,2],[2,3]]]]
-[[[[4,1],2],[1,[6,6]]],[[[2,2],[8,8]],4]]
-[[[[3,7],4],8],[6,[[0,2],3]]]
-[[[[1,8],2],3],[[9,[1,7]],[[0,0],[6,8]]]]
-[[[9,[5,2]],7],[[8,6],[8,[1,2]]]]
-[[[7,[1,0]],[[6,0],[8,4]]],[[[7,8],5],[3,[1,2]]]]
-[[[[2,5],9],[[8,2],0]],0]
-[0,[[[7,5],[4,1]],[5,[6,6]]]]
-[[[[3,6],2],[[1,1],[6,6]]],0]
-[[[[0,9],[2,5]],[2,[3,2]]],[6,3]]
-[3,[[9,[1,4]],[[0,8],[4,6]]]]
-[1,[[5,[5,9]],[9,0]]]
-[[[6,8],4],[[[6,6],2],[[3,9],2]]]
-[5,[[[7,5],[4,8]],0]]
-[[9,[6,6]],[9,[[6,8],[6,4]]]]
-[[[4,8],[0,[2,8]]],[7,[[4,5],[1,6]]]]
-[[[6,[8,6]],2],[[[2,9],[2,4]],[0,2]]]
-[[[0,[5,6]],[[3,8],3]],[[3,1],7]]
-[[1,[8,1]],[1,[6,[7,1]]]]
-[[[5,[9,6]],[3,5]],2]
-[[3,7],[[[2,5],[4,1]],[3,[5,6]]]]
-[[8,7],[[9,6],3]]
-[[[[4,2],[4,8]],[7,[4,5]]],2]
-[[[[6,7],6],3],[[[6,7],4],0]]
-[[[0,1],[[9,1],[2,9]]],9]
-[[[[8,5],[5,8]],[0,7]],[0,[8,[3,2]]]]
-[[4,[[6,5],[1,9]]],[[[0,0],1],6]]
-[[[[9,5],9],[2,[6,3]]],[[2,9],[6,9]]]
-[[[7,[5,0]],1],[7,[[8,7],3]]]
-[[[2,4],2],[[[3,0],6],[[0,2],[9,2]]]]
-[[1,[[7,3],[4,3]]],[[[3,9],[1,1]],[3,6]]]
-[[[[4,7],7],[[7,1],[2,3]]],[1,[[7,6],[5,6]]]]
-[[0,[5,2]],0]
-[[[[6,6],[4,8]],8],[[0,[7,4]],8]]
-[[4,[7,2]],[[[0,8],1],[9,5]]]
-[0,0]
-[[[[3,7],6],3],[3,[[3,3],1]]]
-[[[6,5],7],[[3,5],[[6,4],[4,9]]]]
-[[4,[[7,9],9]],9]
-[5,[8,[[7,4],1]]]
-[[[[2,4],[5,7]],8],[[[7,6],[6,9]],[[3,9],[6,4]]]]
-[[[4,8],3],[[[3,9],7],0]]
-[0,[8,[[4,2],3]]]
-[[[[0,1],[5,8]],[7,2]],[2,4]]
-[[6,[8,[1,9]]],[[[6,5],[8,1]],[7,[6,4]]]]
-[[9,3],[5,[0,6]]]
-[[2,[7,[2,0]]],[[2,1],[5,5]]]
-[[[0,[7,0]],[[0,4],[4,9]]],[8,[[6,1],[6,3]]]]
-[[[[5,7],[3,2]],[0,[5,0]]],[[0,[1,6]],3]]
-[[[[6,3],[9,5]],[9,9]],[[5,[8,3]],[[0,0],[0,3]]]]
-[[6,[4,9]],[[[9,9],[8,4]],4]]
-[0,[2,5]]
-[[[[7,9],[1,2]],[3,3]],[[[7,2],7],[[1,6],0]]]
-[[[[8,0],2],8],[[[1,5],9],9]]
-[[[0,[6,9]],4],[[[4,8],5],4]]
-[[6,[[0,3],4]],[0,[[8,3],1]]]
-[[[1,2],[2,[3,3]]],[6,7]]
-[[0,[[7,4],5]],[3,[[8,2],0]]]
-[[[[0,1],[1,7]],[[2,7],[5,9]]],[[[7,0],0],[8,1]]]
-[[6,4],[3,0]]
-[[[[6,6],4],[5,1]],[7,3]]
-[[[[9,2],3],[8,[4,8]]],7]
-[[5,[[2,2],[9,2]]],[[[1,8],0],[8,[6,3]]]]
-[2,[[0,0],[0,[9,9]]]]
-[[4,4],[[6,5],[6,5]]]
-[[[[9,1],2],4],5]
-[[[[2,1],[3,1]],[[2,6],9]],5]
-[[[9,[0,6]],7],[[8,3],[[8,1],2]]]
-[[[6,[0,0]],[2,[0,0]]],[[[0,4],8],3]]
-[[[[4,1],[2,9]],[6,5]],3]
-[[9,[[9,4],8]],[[[5,5],3],[[3,4],4]]]
-[8,[9,[[0,3],1]]]
-[9,[[[6,0],4],9]]
-[[6,[2,9]],[[[2,7],[5,3]],0]]
-[[[4,1],5],[8,[[0,7],4]]]
-[[[[2,5],5],[[8,2],[8,9]]],[[9,6],[[0,3],[2,3]]]]
-[6,1]
-[[1,7],4]
-[[8,7],0]
-[[[[5,4],7],5],[[[6,1],5],[5,[5,5]]]]
-[[[6,[1,5]],[0,[7,0]]],[[[1,5],3],[5,[1,0]]]]
diff --git a/2021/d18/ex2/ex2.py b/2021/d18/ex2/ex2.py
deleted file mode 100755
index 56c8d48..0000000
--- a/2021/d18/ex2/ex2.py
+++ /dev/null
@@ -1,211 +0,0 @@
-#!/usr/bin/env python
-
-import functools
-import itertools
-import sys
-from copy import deepcopy
-from dataclasses import dataclass
-from typing import Iterator, List, Optional, Tuple
-
-
-@dataclass
-class Tree:
-    parent: Optional["Pair"]
-
-
-@dataclass
-class Pair(Tree):
-    left: Tree
-    right: Tree
-
-
-@dataclass
-class Num(Tree):
-    val: int
-
-
-# True means left, False means right
-Path = List[bool]
-
-
-def solve(input: List[str]) -> int:
-    def make_pair(left: Tree, right: Tree, parent: Optional[Pair] = None) -> Pair:
-        pair = Pair(parent=parent, left=left, right=right)
-        pair.left.parent = pair
-        pair.right.parent = pair
-        return pair
-
-    def make_num(val: int, parent: Optional[Pair] = None) -> Num:
-        return Num(parent=parent, val=val)
-
-    # FIXME: remove this
-    def debug(tree: Tree) -> str:
-        if isinstance(tree, Pair):
-            return f"[{debug(tree.left)},{debug(tree.right)}]"
-        assert isinstance(tree, Num)
-        return str(tree.val)
-
-    def parse() -> List[Tree]:
-        def parse_snailfish_number(line: str) -> Tree:
-            def parse_index(input: str, index: int = 0) -> Tuple[int, Tree]:
-                if input[index] == "[":
-                    left_index, left = parse_index(input, index + 1)
-                    assert input[left_index] == ","  # Sanity check
-                    right_index, right = parse_index(input, left_index + 1)
-                    assert input[right_index] == "]"  # Sanity check
-                    return right_index + 1, make_pair(left, right)
-                res = 0
-                for i in itertools.count(index):
-                    if i < len(input) and input[i] in set(str(i) for i in range(10)):
-                        res = res * 10 + int(input[i])
-                    else:
-                        return i, make_num(res)
-                assert False  # Sanity check
-
-            __, res = parse_index(line)
-            return res
-
-        return [parse_snailfish_number(line) for line in input]
-
-    def explosion_path(number: Tree) -> Optional[Path]:
-        def dfs(number: Pair, path: Path = []) -> Optional[Path]:
-            if (
-                len(path) >= 4
-                and isinstance(number.left, Num)
-                and isinstance(number.right, Num)
-            ):
-                return path
-            if isinstance(number.left, Pair):
-                left_path = dfs(number.left, path + [True])
-                if left_path is not None:
-                    return left_path
-            if isinstance(number.right, Pair):
-                right_path = dfs(number.right, path + [False])
-                if right_path is not None:
-                    return right_path
-            return None
-
-        assert isinstance(number, Pair)  # Sanity check
-        return dfs(number)
-
-    def split_path(number: Tree) -> Optional[Path]:
-        def dfs(number: Pair, path: Path = []) -> Optional[Path]:
-            if isinstance(number.left, Num):
-                if number.left.val >= 10:
-                    return path + [True]
-            else:
-                assert isinstance(number.left, Pair)  # Sanity check
-                if (left_path := dfs(number.left, path + [True])) is not None:
-                    return left_path
-            if isinstance(number.right, Num):
-                if number.right.val >= 10:
-                    return path + [False]
-            else:
-                assert isinstance(number.right, Pair)  # Sanity check
-                if (right_path := dfs(number.right, path + [False])) is not None:
-                    return right_path
-            return None
-
-        assert isinstance(number, Pair)  # Sanity check
-        return dfs(number)
-
-    def explode(number: Tree, path: Path) -> Tree:
-        def walk(number: Tree, reverse: bool) -> Iterator[Tree]:
-            if isinstance(number, Num):
-                yield number
-            else:
-                assert isinstance(number, Pair)  # Sanity check
-                first, second = (
-                    (number.right, number.left)
-                    if reverse
-                    else (number.left, number.right)
-                )
-                yield from walk(first, reverse)
-                yield number
-                yield from walk(second, reverse)
-
-        def next_num(number: Tree, reverse: bool) -> Optional[Num]:
-            if number.parent is None:
-                return None
-            sibling = number.parent.left if reverse else number.parent.right
-            if number is sibling:
-                return next_num(number.parent, reverse)
-            for node in walk(sibling, reverse=reverse):
-                if isinstance(node, Num):
-                    return node
-            return None
-
-        assert isinstance(number, Pair)  # Sanity check
-
-        if len(path) == 0:
-            p, n = next_num(number, reverse=True), next_num(number, reverse=False)
-            if p is not None:
-                assert isinstance(number.left, Num)  # Safety check
-                p.val += number.left.val
-            if n is not None:
-                assert isinstance(number.right, Num)  # Safety check
-                n.val += number.right.val
-            return make_num(0)
-
-        parent, left, right = number.parent, number.left, number.right
-        if path[0]:
-            left = explode(number.left, path[1:])
-        else:
-            right = explode(number.right, path[1:])
-
-        return make_pair(parent=parent, left=left, right=right)
-
-    def split(number: Tree, path: Path) -> Tree:
-        def split_int(num: int, parent: Optional[Pair]) -> Tree:
-            assert num >= 0  # Sanity check
-            left = num // 2
-            right = num - left
-            res = make_pair(left=make_num(left), right=make_num(right), parent=parent)
-            return res
-
-        if len(path) == 0:
-            assert isinstance(number, Num)  # Sanity check
-            return split_int(number.val, number.parent)
-
-        assert isinstance(number, Pair)  # Sanity check
-
-        parent, left, right = number.parent, number.left, number.right
-        if path[0]:
-            left = split(number.left, path[1:])
-        else:
-            right = split(number.right, path[1:])
-
-        return make_pair(parent=parent, left=left, right=right)
-
-    def reduce(number: Tree) -> Tree:
-        path = explosion_path(number)
-        if path is not None:
-            return reduce(explode(number, path))
-        path = split_path(number)
-        if path is not None:
-            return reduce(split(number, path))
-        return number
-
-    def add(left: Tree, right: Tree) -> Tree:
-        return reduce(make_pair(left=left, right=right))
-
-    def magnitude(number: Tree) -> int:
-        if isinstance(number, Num):
-            return number.val
-        assert isinstance(number, Pair)  # Safety check
-        return 3 * magnitude(number.left) + 2 * magnitude(number.right)
-
-    numbers = parse()
-    return max(
-        magnitude(add(deepcopy(l), deepcopy(r)))
-        for l, r in itertools.permutations(numbers, 2)
-    )
-
-
-def main() -> None:
-    input = [line.strip() for line in sys.stdin.readlines()]
-    print(solve(input))
-
-
-if __name__ == "__main__":
-    main()
diff --git a/2021/d18/ex2/input b/2021/d18/ex2/input
deleted file mode 100644
index 1dd0bc9..0000000
--- a/2021/d18/ex2/input
+++ /dev/null
@@ -1,100 +0,0 @@
-[[3,[8,[2,1]]],[[[0,6],[0,2]],3]]
-[[[1,[8,5]],[[3,9],0]],2]
-[5,[[5,[3,8]],[7,4]]]
-[1,[[[0,4],[8,5]],6]]
-[[[1,[0,3]],2],[2,[0,[7,9]]]]
-[[[4,[4,4]],[[7,2],[7,1]]],9]
-[5,[4,4]]
-[[0,[[2,6],[8,9]]],[[4,5],2]]
-[[[8,2],0],3]
-[[9,0],[3,3]]
-[[[[5,2],2],5],5]
-[[[1,6],[[0,4],[7,7]]],[[1,4],[[6,5],5]]]
-[[[[4,1],[4,1]],[2,[5,5]]],[1,[0,[0,6]]]]
-[[[[1,5],1],[8,4]],[9,[3,4]]]
-[[1,[3,3]],[[[7,4],[8,1]],2]]
-[3,[[[2,1],4],[5,4]]]
-[6,[[0,[1,9]],[[4,0],8]]]
-[5,[7,[7,[8,8]]]]
-[[[[6,2],[5,8]],[5,[3,1]]],[[7,9],[[2,0],6]]]
-[[[7,[7,9]],[5,7]],[[[9,3],[6,9]],[[1,2],[2,3]]]]
-[[[[4,1],2],[1,[6,6]]],[[[2,2],[8,8]],4]]
-[[[[3,7],4],8],[6,[[0,2],3]]]
-[[[[1,8],2],3],[[9,[1,7]],[[0,0],[6,8]]]]
-[[[9,[5,2]],7],[[8,6],[8,[1,2]]]]
-[[[7,[1,0]],[[6,0],[8,4]]],[[[7,8],5],[3,[1,2]]]]
-[[[[2,5],9],[[8,2],0]],0]
-[0,[[[7,5],[4,1]],[5,[6,6]]]]
-[[[[3,6],2],[[1,1],[6,6]]],0]
-[[[[0,9],[2,5]],[2,[3,2]]],[6,3]]
-[3,[[9,[1,4]],[[0,8],[4,6]]]]
-[1,[[5,[5,9]],[9,0]]]
-[[[6,8],4],[[[6,6],2],[[3,9],2]]]
-[5,[[[7,5],[4,8]],0]]
-[[9,[6,6]],[9,[[6,8],[6,4]]]]
-[[[4,8],[0,[2,8]]],[7,[[4,5],[1,6]]]]
-[[[6,[8,6]],2],[[[2,9],[2,4]],[0,2]]]
-[[[0,[5,6]],[[3,8],3]],[[3,1],7]]
-[[1,[8,1]],[1,[6,[7,1]]]]
-[[[5,[9,6]],[3,5]],2]
-[[3,7],[[[2,5],[4,1]],[3,[5,6]]]]
-[[8,7],[[9,6],3]]
-[[[[4,2],[4,8]],[7,[4,5]]],2]
-[[[[6,7],6],3],[[[6,7],4],0]]
-[[[0,1],[[9,1],[2,9]]],9]
-[[[[8,5],[5,8]],[0,7]],[0,[8,[3,2]]]]
-[[4,[[6,5],[1,9]]],[[[0,0],1],6]]
-[[[[9,5],9],[2,[6,3]]],[[2,9],[6,9]]]
-[[[7,[5,0]],1],[7,[[8,7],3]]]
-[[[2,4],2],[[[3,0],6],[[0,2],[9,2]]]]
-[[1,[[7,3],[4,3]]],[[[3,9],[1,1]],[3,6]]]
-[[[[4,7],7],[[7,1],[2,3]]],[1,[[7,6],[5,6]]]]
-[[0,[5,2]],0]
-[[[[6,6],[4,8]],8],[[0,[7,4]],8]]
-[[4,[7,2]],[[[0,8],1],[9,5]]]
-[0,0]
-[[[[3,7],6],3],[3,[[3,3],1]]]
-[[[6,5],7],[[3,5],[[6,4],[4,9]]]]
-[[4,[[7,9],9]],9]
-[5,[8,[[7,4],1]]]
-[[[[2,4],[5,7]],8],[[[7,6],[6,9]],[[3,9],[6,4]]]]
-[[[4,8],3],[[[3,9],7],0]]
-[0,[8,[[4,2],3]]]
-[[[[0,1],[5,8]],[7,2]],[2,4]]
-[[6,[8,[1,9]]],[[[6,5],[8,1]],[7,[6,4]]]]
-[[9,3],[5,[0,6]]]
-[[2,[7,[2,0]]],[[2,1],[5,5]]]
-[[[0,[7,0]],[[0,4],[4,9]]],[8,[[6,1],[6,3]]]]
-[[[[5,7],[3,2]],[0,[5,0]]],[[0,[1,6]],3]]
-[[[[6,3],[9,5]],[9,9]],[[5,[8,3]],[[0,0],[0,3]]]]
-[[6,[4,9]],[[[9,9],[8,4]],4]]
-[0,[2,5]]
-[[[[7,9],[1,2]],[3,3]],[[[7,2],7],[[1,6],0]]]
-[[[[8,0],2],8],[[[1,5],9],9]]
-[[[0,[6,9]],4],[[[4,8],5],4]]
-[[6,[[0,3],4]],[0,[[8,3],1]]]
-[[[1,2],[2,[3,3]]],[6,7]]
-[[0,[[7,4],5]],[3,[[8,2],0]]]
-[[[[0,1],[1,7]],[[2,7],[5,9]]],[[[7,0],0],[8,1]]]
-[[6,4],[3,0]]
-[[[[6,6],4],[5,1]],[7,3]]
-[[[[9,2],3],[8,[4,8]]],7]
-[[5,[[2,2],[9,2]]],[[[1,8],0],[8,[6,3]]]]
-[2,[[0,0],[0,[9,9]]]]
-[[4,4],[[6,5],[6,5]]]
-[[[[9,1],2],4],5]
-[[[[2,1],[3,1]],[[2,6],9]],5]
-[[[9,[0,6]],7],[[8,3],[[8,1],2]]]
-[[[6,[0,0]],[2,[0,0]]],[[[0,4],8],3]]
-[[[[4,1],[2,9]],[6,5]],3]
-[[9,[[9,4],8]],[[[5,5],3],[[3,4],4]]]
-[8,[9,[[0,3],1]]]
-[9,[[[6,0],4],9]]
-[[6,[2,9]],[[[2,7],[5,3]],0]]
-[[[4,1],5],[8,[[0,7],4]]]
-[[[[2,5],5],[[8,2],[8,9]]],[[9,6],[[0,3],[2,3]]]]
-[6,1]
-[[1,7],4]
-[[8,7],0]
-[[[[5,4],7],5],[[[6,1],5],[5,[5,5]]]]
-[[[6,[1,5]],[0,[7,0]]],[[[1,5],3],[5,[1,0]]]]