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 Ruby (2.3.3) (judge verdict: Accepted)

first_line = STDIN.gets.strip

buttons = first_line.split(' ').map(&:to_i)
total = 0

2.times do |_i|
  v = 0
  if buttons[0] >= buttons[1] then
    v = buttons[0]
    buttons[0] = buttons[0] - 1
  else
    v = buttons[1]
    buttons[1] = buttons[1] - 1
  end
  total += v
end

puts total