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: Wrong Answer)

using System;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] array = Console.ReadLine().Split(' ');


            int a = int.Parse(array[0]);

            int b = int.Parse(array[1]);

            int max;

            for (max = 0; max < 2; max++)
            {
                if (a < b)
                {
                    max = b;
                    b -= 1;
                    Console.WriteLine(max += b);
                }
                else if(a > b)
                {
                    max = a;
                    a -= 1;
                    Console.WriteLine(max += a);

                }
                else if(a == b)
                {
                    max = b;
                    b -= 1;
                    Console.WriteLine(max += b);
                }
                
                
            }
                  
        }
    }
}