Problem:
Score : 100 points

Problem Statement

There are two buttons, one of size A and one of size B.

When you press a button of size X, you get X coins and the size of that button decreases by 1.

You will press a button twice. Here, you can press the same button twice, or press both buttons once.

At most how many coins can you get?

Constraints

All values in input are integers.

3 \leq A, B \leq 20

Input

Input is given from Standard Input in the following format:

A B

Output

Print the maximum number of coins you can get.

Sample Input 1

5 3

Sample Output 1

9

You can get 5 + 4 = 9 coins by pressing the button of size 5 twice, and this is the maximum result.

Sample Input 2

3 4

Sample Output 2

7

Sample Input 3

6 6

Sample Output 3

12

Solution in Scala (2.11.7) (judge verdict: Wrong Answer)

object Main extends App {

  val s = io.StdIn.readLine

  var diff1 = 0
  var diff2 = 0

  for (i <- 0 until s.size) {
    val p1 = if (i % 2 == 0) '0' else '1'
    val p2 = if (i % 2 == 0) '1' else '0'

    // println(s"$p1 $p2 ${s(i)}")

    if (s(i) != p1)
      diff1 += 1

    if (s(i) != p2)
      diff2 += 1
  }

  println(math.min(diff1,diff2))

}