// editor4
#include<stdio.h>
int main()
{
    int n;
    scanf("%d", &n);
    
    if (n < 0)
    {
        printf("Invalid input\n");
        return 0;
    }
    
    long long factorial = 1; 
    for (int i = 1; i<= n; i++)
    {
        factorial *= i;
    }
    printf("%11lld\n", fact);
    return 0;
}