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 Perl (v5.18.2) (judge verdict: Accepted)

#!/usr/bin/perl
#= CPAN mocules =====================================================#
use strict;				# strictモード
use warnings;			# 警告有効

#= Global values ====================================================#
#= Local routines ===================================================#
sub main(){
	my @inData;
	foreach (0..2){
		$inData[$_] = <>;
		chomp $inData[$_];
	}

	my $tate = $inData[0];
	my $yoko = $inData[0];

	$tate -= $inData[1];
	$tate++;
	$yoko -= $inData[2];
	$yoko++;
	
	print $tate * $yoko;
	print "\n";

	return 0;
}

#----- 実行 -----#
exit( main() );