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: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace ReadLine01
{
    class Program
    {
        static void Main(string[] args)
        {
            int x;
            x=int.Parse(Console.ReadLine());
            int y;
            y =int.Parse(Console.ReadLine());
			int sum;
          
			if(x > y){
				sum = x + (x-1);
            }else if(x < y){
              	sum = y + (y-1);
            }else{
                sum = x + y;
            }
 
          Console.Write(sum);
 
        }
    }
}