# The Titan

Intra Metropolitan Univer...
Limits 1s, 512 MB

The Titan, a giant ship started its journey on the dark sea. It was going to the North America.

On the way it affected by storms and started drowning on the sea. The sailors of The Titans jumped on the water, swimming hard and reached in a tropical island. When the night fall down an one eyed man eater demon appeared and it about to eat them. The sailors frightened and asked for mercy .

The Demon laughed Haw! Haw! Haw! and said he will asked them a question and if they able to answer the question he will let them go.

He asked them to find out the summation of the square of first N natural numbers . What will be your answer if you were in their place??

Example: If N = 5, the the answer is,

M = 1^2 + 2^2 + 3^2 + 4^2 + 5^2 = 55

## Input

The Input line contains a single integer N (1 ≤ N ≤ 10^3).

## Output

Print a single integer M (summation of the square of first N natural numbers).

## Samples

InputOutput
5

55

InputOutput
9
285

InputOutput
15
1240