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;

namespace AtCoder.ABC._124
{
    class a
    {
        static void Main(string[] args)
        {
            var line = Console.ReadLine().Trim();
            var spl = line.Split(' ');
            var A = int.Parse(spl[0]);
            var B = int.Parse(spl[1]);
            if (A == B)
            {
                Console.WriteLine(A*2);
            }
            else
            {
                Console.WriteLine(Math.Max(A,B) * 2 - 1);
            }
        }
    }
}