/*

Description:

Task

Below we will define what and n-interesting polygon is and your task is to find its area for a given n.

A 1-interesting polygon is just a square with a side of length 1. An n-interesting polygon is obtained by taking the n – 1-interesting polygon and appending 1-interesting polygons to its rim side by side. You can see the 1-, 2- and 3-interesting polygons in the picture below.

Example

For n = 1, the output should be 1;

For n = 2, the output should be 5;

For n = 3, the output should be 13.

Input/Output

[input] integer n

Constraints: 1 ≤ n < 10000. [output] an integer The area of the n-interesting polygon. */ function shapeArea(n) { return Math.pow(n,2) + Math.pow(n-1,2); }