Problem:
Score : 100 points

Problem Statement

It has been decided that a programming contest sponsored by company A will be held, so we will post the notice on a bulletin board.

The bulletin board is in the form of a grid with N rows and N columns, and the notice will occupy a rectangular region with H rows and W columns.

How many ways are there to choose where to put the notice so that it completely covers exactly HW squares?

Constraints

1 \leq H, W \leq N \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
H
W

Output

Print the answer.

Sample Input 1

3
2
3

Sample Output 1

2

There are two ways to put the notice, as follows:

### ...
### ###
... ###

Here, # represents a square covered by the notice, and . represents a square not covered.

Sample Input 2

100
1
1

Sample Output 2

10000

Sample Input 3

5
4
2

Sample Output 3

8

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 CompetitiveProgCsLib
{
	class MainProg
	{
		static string R => Console.ReadLine();
		static int RI => int.Parse(R);
		static double RD => double.Parse(R);
		static int[] RIs => R.Split(' ').Select(int.Parse).ToArray();
		static double[] RDs => R.Split(' ').Select(double.Parse).ToArray();
		static void Out(object obj) => Console.WriteLine(obj);
		static void OutLine<T>(IEnumerable<T> obj, string separateChar) => Out(String.Join(separateChar, obj));
		static void Outb(bool b) => Out(b ? "Yes" : "No");
		static void OutB(bool b) => Out(b ? "YES" : "NO");
		static bool IsIn(int y, int x, int h, int w) => 0 <= x && x < w && 0 <= y && y < h;

		static void Main(string[] args)
		{
			var n = RI;
			var h = RI;
			var w = RI;
			Out((n - h + 1) * (n - w + 1));
		}
	}
}