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 abc124_a
{
    class Program
    {
        static void Main(string[] args)
        {
            //入力
            string[] input = Console.ReadLine().Split(' ');
            int a = Convert.ToInt32(input[0]);
            int b = Convert.ToInt32(input[1]);
            int max = 0;


            //ボタン処理
            for (int i = 0; i < 2; i++)
            {
                if (a >= b)
                {
                    max += a;
                    a--;
                }
                else
                {
                    max += b;
                    b--;
                }
            }
            //出力
            Console.WriteLine(max);
        }
    }
}