2017-10-24 15:41:19 +00:00
|
|
|
|
# -*- coding: utf-8 -*-
|
|
|
|
|
|
'''
|
|
|
|
|
|
Problem:
|
|
|
|
|
|
The sum of the squares of the first ten natural numbers is,
|
|
|
|
|
|
1^2 + 2^2 + ... + 10^2 = 385
|
|
|
|
|
|
The square of the sum of the first ten natural numbers is,
|
|
|
|
|
|
(1 + 2 + ... + 10)^2 = 552 = 3025
|
|
|
|
|
|
Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 − 385 = 2640.
|
|
|
|
|
|
Find the difference between the sum of the squares of the first N natural numbers and the square of the sum.
|
|
|
|
|
|
'''
|
2017-11-25 09:23:50 +00:00
|
|
|
|
from __future__ import print_function
|
2018-10-19 08:30:31 +00:00
|
|
|
|
n = int(raw_input())
|
2017-10-24 15:41:19 +00:00
|
|
|
|
suma = n*(n+1)/2
|
|
|
|
|
|
suma **= 2
|
|
|
|
|
|
sumb = n*(n+1)*(2*n+1)/6
|
2017-11-25 09:23:50 +00:00
|
|
|
|
print(suma-sumb)
|
