#include <cstdio>
#include <iostream>
#include <cstring>

using namespace std;

int N, sol;

int main ( void ){
  scanf("%d",&N);

  for ( int i = 0; i <= N; ++i )
    for ( int j = i; j <= N; ++j )
      sol += i + j;

  printf("%d\n",sol);

  return 0;
}