#include <iostream>
using namespace std;

int main() {
    int n;
    int result = 1;
    cin >> n;

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

    cout << result << endl;
    return 0;
}
    
/**************************************************************
	Problem: 1004
	User: fuyijun
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/