#include<stdio.h>
int min()
{
int n;
long long factorial = 1;
if(scanf("%d", &n)!= 1)
return 0;
if(n < 0) {
        printf("Invalid input");
        return 0;
    }
    else {
        for (int i = 1; i <= n;i++) {
            factorial *=i;
        }
        printf("%lld", factorial);
    }
    return 0;
}