文件目录

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int s1 = 0, s2 = 0;
    for (int i = 1; i <= n; i++)
    {
        s1 += i;
        s2 += s1;
    }
    cout << s2;
    return 0;
}