//#define _USE_MATH_DEFINES
//#include <cmath>
#include <iostream>
//#include <stdio.h>
//#include <stdlib.h>
//#include <iomanip>
//#include <vector>
//#include <string>
//#include <algorithm>
//#include <functional>
//#include <time.h>
//#include <sstream>
//#include <queue>

using namespace std;


int main(){

	long long ans;
	int n;

	cin >> n;

	ans = 1;
	for (int i = 1; i <= n; i++){
		ans *= i;
	}

	cout << ans << endl;

	return 0;
}