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: Runtime Error)

using System;
using System.Text;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 ans = 0;
        for(int i = 0; i < 2; i++)
		{
			if (a > b) { ans += a;
				a--;
			}
			else { ans += b;
				b--;
			}
		}
		Console.WriteLine(ans);

	}
}