diff --git a/day04.py b/day04.py
new file mode 100644
index 0000000..4c4c5cd
--- /dev/null
+++ b/day04.py
@@ -0,0 +1,24 @@
+import fileinput
+
+#
+# Part 1
+#
+cards = []
+part1 = 0
+for i, line in enumerate(fileinput.input()):
+    card = line.rstrip().split(": ")[1]
+    (winning, owned) = ({int(i) for i in h.split()} for h in card.split(" | "))
+    count = len(winning & owned)
+    cards.append(count)
+    part1 += 1 << count - 1 if count else 0
+
+#
+# Part 2
+#
+dp = [0] * len(cards)
+part2 = 0
+for i in range(len(cards)):
+    dp[i] = 1 + sum(dp[i - cards[-i - 1] : i])
+    part2 += dp[i]
+
+print(part1, part2)