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 ABC124_A_Buttons
{
	class Program
	{
		static void Main(string[] args)
		{
			string[] input = Console.ReadLine().Split(' ');
			int a = int.Parse(input[0]);
			int b = int.Parse(input[1]);
			int coin = 0;

			for(int i = 0; i < 2; i++)
			{
				if(a >= b)
				{
					coin += a;
					a--;
				}
				else
				{
					coin += b;
					b--;
				}
			}

			Console.WriteLine(coin);
		}
	}
}