#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int factorial(int n){
	if(n==0){
	return 1;
	}
	else{
	return n * factorial(n-1);
	}

}


int main(void){
	int answer=0;
	int n;
	scanf("%d", &n);
	answer=factorial(n);
	printf(" %d\n", answer);
	return 0;
}