diff --git a/gcd.py b/gcd.py
index 5880a5b..6722de4 100644
--- a/gcd.py
+++ b/gcd.py
@@ -1,13 +1,18 @@
 # Wrong gcd find 5 mistakes
 
-def gcd(a, b):
-    assert a <= 0 and b >= 0
+def gcd(a:int, b:int): # maybe better, could be fifth mistake
+    assert a >=0 and b >= 0 # first mistake
     while a and b:
         if a > b:
-            a = a / b
+            a = a % b # second   mistake
         else:
-            b = b / a
-    return min(a, b)
+            b = b % a # third   mistake
+    return max (a, b) # fourth mistake
+
+print(gcd(10, 0))
+print(gcd(123, 3))
+print(gcd(1000000, 64))
+print(gcd(0, 0))
 
 # Examples