#include "iostream"
using namespace std;
long long sum = 0 , n , h = 0;
int main() {
cin >> n;
for (int i = 1 ; i <= n ; i++) {
sum += (1 + i ) * i / 2;//开个挂,高斯公式
}
cout << sum << endl;
return 0;
}

#include "iostream"
using namespace std;
long long sum = 0 , n , h = 0;
int main() {
cin >> n;
for (int i = 1 ; i <= n ; i++) {
sum += (1 + i ) * i / 2;//开个挂,高斯公式
}
cout << sum << endl;
return 0;
}