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.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Buttons
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] buttons = Console.ReadLine().Split(' ');
            int[] num = buttons.Select(int.Parse).ToArray();
            int sum = 0;
            int n1 = 0;
            for(int n = 0; n <= 1; ++n)
            {
                int c = num.Max();
                sum += c;
                if (c == num[n1])
                {
                    num[n1] -= 1;
                }
                else
                {
                    num[n1 + 1] -= 1;
                }
                
            }
            Console.WriteLine(sum);
        }
    }
}