#45793: Python
wming0264@gmail.com
(User)
try:
while True:
n = int(input())
print((n ** 3 + n * 5 + 6) // 6)
except EOFError:
pass
try:
while True:
n = int(input())
print((n ** 3 + n * 5 + 6) // 6)
except EOFError:
pass