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)

i = gets.chomp.split.map(&:to_i)
i[2] = i[0] - 1
i[3] = i[1] - 1
max = 0
max2 = 0
4.times do |hoge|
    if max < i[hoge] then
        if max != 0 and 1 <= hoge then
            max2 = max
        end
        max = i[hoge]
    elsif max2 < i[hoge] then
        max2 = i[hoge]
    end
end
puts max + max2