diff --git a/day3/common.py b/day3/common.py
new file mode 100644
index 0000000..88dc257
--- /dev/null
+++ b/day3/common.py
@@ -0,0 +1,3 @@
+def parse(filename: str) -> str:
+    with open(filename) as f:
+        return f.read()
diff --git a/day3/part1.py b/day3/part1.py
new file mode 100755
index 0000000..69b2cf0
--- /dev/null
+++ b/day3/part1.py
@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+import re
+
+from common import parse
+
+
+def solve(input: str) -> int:
+    regex = r"mul\((\d+),(\d+)\)"
+    muls = re.findall(regex, input)
+    return sum(map(lambda x: int(x[0]) * int(x[1]), muls))
+
+
+def main():
+    print(solve(parse("input")))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/day3/part2.py b/day3/part2.py
new file mode 100755
index 0000000..d57c6b7
--- /dev/null
+++ b/day3/part2.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+import re
+
+from common import parse
+
+
+def solve(input: str, debug=False) -> int:
+    regex = r"(mul\((\d+),(\d+)\)|do\(\)|don't\(\))"
+    prog = re.findall(regex, input)
+    the_sum = 0
+    enabled = True
+    for stance in prog:
+        if debug:
+            print(stance[0], end=": ")
+        if enabled and stance[0].startswith("mul"):
+            if debug:
+                print("multiplying")
+            the_sum += int(stance[1]) * int(stance[2])
+        elif enabled and stance[0] == "don't()":
+            if debug:
+                print("disabling")
+            enabled = False
+        elif not enabled and stance[0] == "do()":
+            if debug:
+                print("enabling")
+            enabled = True
+        else:
+            if debug:
+                print("noop")
+    return the_sum
+
+
+def main():
+    print(solve(parse("input")))
+
+
+if __name__ == "__main__":
+    main()