#include<iostream>
using namespace std;
int main(){
    ios::sync_with_stdio(false);
    int n, ans = 0, fac = 1;
    cin >> n;
    for(int i = 1; i <= n; i++){
        fac *= i; ans += fac;
    }
    cout << ans << endl;
    return 0;
}

#include<iostream>
using namespace std;
int a[12] = {1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600};
int main(){
    ios::sync_with_stdio(false);
    int n, ans = 1;
    cin >> n;
    for(int i = 1; i < n; i++)ans += a[i];
    cout << ans << endl;
    return 0;
}