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.Linq;
using System.Collections.Generic;
class Program
{
    static void Main()
    {
        var n = int.Parse(RL());
        var h = int.Parse(RL());
        var w = int.Parse(RL());

        var count = 0;
        for (int i = 0; i < n - h + 1; i++)
        {
            for (int j = 0; j < n - w + 1; j++)
            {
                count++;
            }
        }

        Console.WriteLine(count);
    }

    static string RL()
    {
        return Console.ReadLine();
    }

    static void WL(string str)
    {
        Console.WriteLine(str);
    }
}