// editor3
#include<stdio.h>
int main()
{
    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("%1111d",factorial);
    }
    return 0;
}