#include <iostream>

using namespace std;

int main()
{
    int n;
    cin >> n;
    int fact[n];
    fact[0] = 1;
    fact[1] = 1;
    for(int i = 2; i <= n; i++) {
        fact[i] = fact[i - 1] * i;
    }
    cout << fact[n] << endl;
    return 0;
}