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)

ab = gets.to_s
ab = ab.split(" ")
a = ab[0].to_i
b = ab[1].to_i
sum = 0

if a > b
  sum += a
  a = a - 1
else
  sum += b
  b = b - 1
end

if a > b
  sum += a
  a = a - 1
else
  sum += b
  b = b - 1
end
puts sum