diff --git a/2021/d03/ex1/ex1.py b/2021/d03/ex1/ex1.py
new file mode 100755
index 0000000..7519004
--- /dev/null
+++ b/2021/d03/ex1/ex1.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+
+import sys
+from typing import List
+
+
+def solve(input: List[int]) -> int:
+    gamma, epsilon = 0, 0
+    bit = 1
+
+    while any(map(bool, input)):
+        num_bits = sum(n % 2 for n in input)
+        if num_bits >= len(input) / 2:
+            gamma += bit
+        else:
+            epsilon += bit
+        input = [n // 2 for n in input]
+        bit *= 2
+
+    return gamma * epsilon
+
+
+def main() -> None:
+    input = [int(line, 2) for line in sys.stdin.readlines()]
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()