n = int(input())
i = 1
kaisuu = 1
kakerukazu = 1
ans = 0
while i <= n:
  for ipp in range(kaisuu):
    ans += i ** kakerukazu
    if kakerukazu < 3:
      kakerukazu += 1
    else:
      kakerukazu = 1
  i += 1
print(ans)