Description

Below we will define an n-interesting polygon. Your task is to find the area of a polygon 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-, 3- and 4-interesting polygons in the picture below.

Example

• For n = 2, the output should be shapeArea(n) = 5;
• For n = 3, the output should be shapeArea(n) = 13.

Input/Output

• [execution time limit] 4 seconds (js)

• [input] integer n

Guaranteed constraints: 1 \leq \text{n} \le 10^4.

• [output] integer

The area of the n-interesting polygon.

[JavaScript (ES6)] Syntax Tips

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// Prints help message to the console
// Returns a string
function helloWorld(name) {
    console.log("This prints to the console when you Run Tests");
    return "Hello, " + name;
}