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: Runtime Error)

while
  A = input()
  if A < 3
    print("A is not collect.\n")
  	return
  end
  B = input()
  if B > 20
    print("B is not collect.\n")
	return
  end
end

if A-1 > B
  print(2*A -1, "\n")
elsif B-1 > A
  print(2*B - 1, "\n")
else A == B
  print(A+B, "\n")
end