#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;
}