팩토리얼

#include <algorithm>
#include <iostream>
#include <stdio.h>
#include <vector>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <string>
#include <cmath>
#include <time.h>
using namespace std;

bool arr[10000001];

int main() {
	//freopen("input.txt", "rt", stdin);

	int num;

	scanf("%d", &num);

	if (num == 0) {
		printf("1");
		return 0;
	}
	int result = 1;
	while (num >= 1) {
		result = result * num;
		num--;
	}
	printf("%d", result);


	return 0;
}