text: function shapeArea(n) {
      return Math.pow(n, 2) + Math.pow(n - 1, 2)
  }
  
  // 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 ≤ n < 104.
  
  //     [output] integer
  
  //     The area of the n-interesting polygon.
  