#include <iostream>
#include <vector>
#include <queue>
using namespace std;

int factorial(int n) {
    if(n == 1) {
        return 1;
    }
    return factorial(n - 1) * n;
}
int main() {
    int n;
    cin >> n;

    cout << factorial(n) << endl;

    return 0;
}