diff --git a/gcd.py b/gcd.py
index 5880a5b..364b1cf 100644
--- a/gcd.py
+++ b/gcd.py
@@ -1,17 +1,19 @@
 # Wrong gcd find 5 mistakes
 
 def gcd(a, b):
-    assert a <= 0 and b >= 0
-    while a and b:
+    assert (a >= 0 and b >= 0 and (a != 0 or b != 0)), \
+        "Check params, should be two or more integers, which are not all zero" #1
+    while (a!=0 and b!=0): #2
         if a > b:
-            a = a / b
+            a = a % b #3
         else:
-            b = b / a
-    return min(a, b)
+            b = b % a #4
+    return max(a, b) #5
 
 # Examples
 
-# gcd(10, 0) => 10
-# gcd(123, 3) => 3
-# gcd(1000000, 64) => 64
-# gcd(0, 0) => 0
+# print(gcd(10, 0)) #=> 10
+# print(gcd(123, 3)) # => 3
+# print(gcd(1000000, 64)) # => 64
+# print(gcd(0, 0)) #=> exc
+# print(gcd(54,24)) #=> 6
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