Problem:
Score : 100 points

Problem Statement

In K-city, there are n streets running east-west, and m streets running north-south. Each street running east-west and each street running north-south cross each other. We will call the smallest area that is surrounded by four streets a block. How many blocks there are in K-city?

Constraints

2 ≤ n, m ≤ 100

Input

Input is given from Standard Input in the following format:

n m

Output

Print the number of blocks in K-city.

Sample Input 1

3 4

Sample Output 1

6

There are six blocks, as shown below:

Sample Input 2

2 2

Sample Output 2

1

There are one block, as shown below:

Solution in PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
	fscanf(STDIN, "%d %d", $n, $m);
	$street = $n + $m;
	if($street === 4){
		echo 1;
	}else if( $street > 4){
		$street -= 4;
		echo $street *2;
	}
?>