#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n; 
    int result = 1;
    for (int i = 1; i <= n; ++i) {
        result *= i;
    }
    cout << result << endl;  
    return 0;
}
/**************************************************************
	Problem: 1004
	User: fuhoubin
	Language: C++
	Result: Accepted
	Time:19 ms
	Memory:2072 kb
****************************************************************/