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 Scala (2.11.7) (judge verdict: Runtime Error)

object Main {
  def main(args: Array[String]): Unit = {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt
    val a = List.fill(n)(sc.nextInt)
 
    val multipleOf4 = a.filter( _ % 4 == 0)
    val multipleOf2 = a.filter( _ % 2 == 0)
    val ans = if (multipleOf4.length <= a.length / 2) {
      if (multipleOf4.length + (multipleOf2.length - multipleOf4.length) / 2 <= a.length / 2) "Yes"
      else "No"
    }
    else "Yes"
 
    println(ans)
  }
}