diff --git a/gcd.py b/gcd.py
index 5880a5b..3192995 100644
--- a/gcd.py
+++ b/gcd.py
@@ -1,17 +1,26 @@
 # Wrong gcd find 5 mistakes
 
 def gcd(a, b):
-    assert a <= 0 and b >= 0
+    assert a >= 0 and b >= 0
     while a and b:
         if a > b:
-            a = a / b
+            if a % b == 0:
+                return b
+            else:
+                a = a % b
         else:
-            b = b / a
-    return min(a, b)
+            if b % a == 0:
+                return a
+            else:
+                b = b % a
+    return a + b
 
+print ('result: ',gcd(10, 0))
+print ('result: ',gcd(123, 3))
+print ('result: ',gcd(10000000, 64))
+print ('result: ',gcd(0, 0))
 # Examples
-
-# gcd(10, 0) => 10
-# gcd(123, 3) => 3
-# gcd(1000000, 64) => 64
-# gcd(0, 0) => 0
+#gcd(10, 0) #=> 10
+#gcd(123, 3) #=> 3
+#gcd(1000000, 64) #=> 64
+#gcd(0, 0) #=> 0