diff --git a/2015/4/coin.py b/2015/4/coin.py
new file mode 100644
index 0000000..1f45e10
--- /dev/null
+++ b/2015/4/coin.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+import sys, hashlib
+key = sys.stdin.readline().strip()
+
+def findmd5(n):
+    result = "                            "
+    i = 0
+    while result[:n] != "0" * n:
+        i = i + 1
+        result = hashlib.md5((key + str(i)).encode('utf-8')).hexdigest()
+    return i
+
+print(findmd5(5), findmd5(6))