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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AtCoder {
	class Program {
		#region Reserve
		static int cin() { return cin(-1); }
		static int cin(int D) {
			string s = Console.ReadLine();
			if (string.IsNullOrEmpty(s))
				return D;
			return int.Parse(s);
		}
		static long cln(long D = -1) {
			string s = Console.ReadLine();
			if (string.IsNullOrEmpty(s))
				return D;
			return long.Parse(s);
		}
		static int[] cins(char spliter) {
			string s = Console.ReadLine();
			if (string.IsNullOrEmpty(s))
				return new int[] { };
			string[] ss = s.Split(spliter);
			var Res = new int[ss.Length];
			for (int i = 0; i < ss.Length; i++)
				Res[i] = int.Parse(ss[i]);
			return Res;
		}
		static int[] cins() { return cins(' '); }
		static void print(object j) { Console.WriteLine(j.ToString()); }
		static void print(string j) { Console.WriteLine(j); }
		static string read() { return Console.ReadLine(); }
		#endregion

		static void Main(string[] args) {
			var N = cin();
			var A = cin();
			print(N * N - A);
		}
	}
}