Update app.py

app.py

@@ -14,7 +14,11 @@ def factorial(n :int ) -> int:
     Args:
         n: an int number to calculate factorial
     """
-    return n*factorial(n-1)
+    res = n
+    while n>1:
+      res=res*(n-1)
+      n=n-1
+    return res
     
 
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