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