diff --git a/day03.py b/day03.py
new file mode 100644
index 0000000..9b55a34
--- /dev/null
+++ b/day03.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+
+import re
+
+with open("day03") as f:
+    i = f.read()
+
+# 1
+
+pat = re.compile(r"mul\(([0-9]+),([0-9]+)\)")
+
+muls = re.findall(pat, i)
+
+res = 0
+for mul in muls:
+    res += int(mul[0]) * int(mul[1])
+
+
+# 2
+
+pat = re.compile(r"(mul\(([0-9]+),([0-9]+)\)|do\(\)|don't\(\))")
+
+muls = re.findall(pat, i)
+
+res = 0
+
+def consume_disabled(muls):
+    for mul in muls:
+        if mul[0] == "do()":
+            consume_enabled(muls)
+
+def consume_enabled(muls):
+    global res
+    for mul in muls:
+        if mul[0] == "don't()":
+            consume_disabled(muls)
+        if mul[0].startswith("mul"):
+            res += int(mul[1]) * int(mul[2])
+
+gen = (m for m in muls)
+consume_enabled(gen)
+
+print(res)