Description

We have introduced the loop and condition concept in our course, you can use these concepts to finish the following task.

Calculate N! = 1×2×...×(N-1)×N. 

Note that

1. You DO NOT need to consider the number exceed the range of integer or long long data type. 
2. 0! = 1

 

Input

A line of text with a number.

Output

A line with the factorial result with the string "is the answer".

Sample Input  Download

Sample Output  Download

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