#include <bits/stdc++.h>
char *gets(char *);
int main() {
  char buf[100];
  long long n, ans;
  while (gets(buf) != NULL) {
    n = atoi(buf) + 1;
    ans = n * (n + 1) * (n + 2) / 6;
    printf("%lld\n", ans);
  }
  return 0;
}
