#include <stdio.h>
long fac(int n){
	if(n == 1){
		return 1;
	}else{
		return (fac(n-1)*n) % 1000000000000;
	}
}
int main(void){
	long n;
	scanf("%ld", &n);
	printf("%ld\n", fac(n));
	return 0;
}