diff --git a/2021/d01/ex1/ex1.py b/2021/d01/ex1/ex1.py
new file mode 100755
index 0000000..b9c93da
--- /dev/null
+++ b/2021/d01/ex1/ex1.py
@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+
+import itertools
+import sys
+from typing import List
+
+
+def solve(input: List[int]) -> int:
+    return sum(prev < cur for (prev, cur) in itertools.pairwise(input))
+
+
+def main() -> None:
+    input = [int(line) for line in sys.stdin.readlines()]
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()