#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("%11d", factorial);
}
return 0;
}