#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll n;
    cin >> n;
    ll ans = 0;
    for(ll i = 1; i <= n; i++){
        ll cnt = i % 3, d = 1;
        if(cnt == 0) cnt = 3;
        while(cnt--) d *= i;
        ans += d;
    }
    cout << ans << '\n';
}