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;

class Program
{
  static int Count(bool evenOne, string s) {
    int total = 0;
    for (int i = 0; i < s.Length; ++i) {
      if (s[i] == (i % 2 == 0 ? (evenOne ? '1' : '0') : (evenOne ? '0' : '1'))) {
        continue;
      }
      total++;
    }
    return total;
  }
  
  static void Main(string[] args)
  {
    var tiles = Console.ReadLine();
    Console.WriteLine(Math.Min(Count(true, tiles), Count(false, tiles)));
  }
}