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