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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.CodeDom.Compiler;
using System.Linq;
using System.Text.RegularExpressions;

class Program
{
	static void Main(string[] args)
	{
		long[] inputLongArray = Console.ReadLine().Split(' ').Select(i => long.Parse(i)).ToArray();

		long n = inputLongArray[0] - 1;
		long m = inputLongArray[1] - 1;

		Console.WriteLine(n * m);
	}
}