#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>

int Fac(int n)

{

int i = 0;

int ret = 1;

for (i = 1; i <= n; i++)

{

 ret *= i;

}

return ret;

}

int main()

{

int n = 0;

scanf("%d", &n);

int ret = Fac(n);

printf("%d\n", ret);

return 0;

}