#include <iostream>

int main(int, char *[])
{
  int N;
  std::cout << "Forneca o valor de N: ";
  std::cin >> N;
  int s{0};
  for (int i = 1; i <= N; ++i) {
    s += (i * i - i);
  }
  std::cout << "A somatoria vale " << s << std::endl;
  return 0;
}