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

using System;
using System.Linq;
class abc124_c{
  static void Main(){
    var cin=Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
    var a=cin[0];
    var b=cin[1];
    var coin=0;
    
    for(int i=0;i<2;i++){
      if(a<b){
        coin+=b;
        b--;
      } else {
        coin+=a;
        a--;
      }
    }
    
    Console.WriteLine(coin);
    return;
  }
}