Calculate the formula

Time Limit: 1000/1000 MS (Java/Others)

Memory Limit: 32768/32768 K (Java/Others)

Description

You just need to calculate the sum of the formula: 1^2+3^2+5^2+……+ n ^2.

Input

In each case, there is an odd positive integer n.

Output

Print the sum. Make sure the sum will not exceed 2^31-1

Sample Input

3

Sample Output

10

Hint

威士忌

Source

HDU 2007-11 Programming Contest_WarmUp

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