Problem:
Score : 100 points

Problem Statement

We have an N \times N square grid.

We will paint each square in the grid either black or white.

If we paint exactly A squares white, how many squares will be painted black?

Constraints

1 \leq N \leq 100

0 \leq A \leq N^2

Inputs

Input is given from Standard Input in the following format:

N
A

Outputs

Print the number of squares that will be painted black.

Sample Input 1

3
4

Sample Output 1

5

There are nine squares in a 3 \times 3 square grid.
Four of them will be painted white, so the remaining five squares will be painted black.

Sample Input 2

19
100

Sample Output 2

261

Sample Input 3

10
0

Sample Output 3

100

As zero squares will be painted white, all the squares will be painted black.

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

#region Using directives
using System;
using static System.Console;
using static System.Convert;
using System.Collections.Generic;
#endregion

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = ToInt32(ReadLine());
            int k = ToInt32(ReadLine());
            string[] input = ReadLine().Split();
            List<int> arr = new List<int>();
            foreach (string s in input)
                arr.Add(ToInt32(s));
            List<int> answ = new List<int>();
            for(int i = 1; i <= n; i++)
            {
                int f = arr[i - 1] * 2;
                int s = (k - arr[i - 1]) * 2;
                answ.Add(System.Math.Min(f, s));
            }
            int ans = 0;
            foreach (int x in answ)
                ans += x;
            WriteLine(ans);
            ReadKey();
        }
    }
}