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;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            //[summary]A - Bulletin Board
            var lines = ReadLines(3);
            int n = lines[0];
            int h = lines[1];
            int w = lines[2];
            int count = 0;

            for(int y = 0; y < n; y++)
            {
                for(int x = 0; x < n; x++)
                {
                    if (y + h <= n && x + w <= n)
                    {
                        count++;
                    }
                }
            }

            Console.WriteLine(count);
        }

        static List<int> ReadLines(int count = 0)
        {
            //[summary]コンソールの値を読み込む
            var list = new List<int>();

            //読み込む行数が未指定のときは、1行目の値を"count"とみなす
            if (count == 0)
            {
                string s = Console.ReadLine().TrimEnd();
                count = int.Parse(s);
            }

            for (int i = 0; i < count; i++)
            {
                string s = Console.ReadLine().TrimEnd();
                list.Add(int.Parse(s));
            }

            return list;
        }
    }
}