diff --git a/conundrum.py b/conundrum.py
new file mode 100644
index 0000000..7257b11
--- /dev/null
+++ b/conundrum.py
@@ -0,0 +1,4 @@
+secret = input().strip()
+per = "PER" * (len(secret) // 3)
+d = sum([1 if x != y else 0 for x, y in zip(secret, per)])
+print(d)