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 JavaScript (node.js v5.12) (judge verdict: Accepted)

function main(input) {
  input=input.trim();
  const n = parseInt(input.split(" ")[0], 10);
  const m = parseInt(input.split(" ")[1], 10);
  console.log((n-1)*(m-1));
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));