/******************************************************************************
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#include <stdio.h>
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
int F(int n){
if(n == 0){
return 1;
}
return n * F(n - 1);
}
int main()
{
int n;
cin >> n;
cout << F(n) <<endl;
return 0;
}