p03071 AtCoder Beginner Contest 124 - Buttons_16110
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.

Examples

Input

5 3


Output

9


Input

3 4


Output

7


Input

6 6


Output

12
a, b = map(int,raw_input().split())
if a >= b + 1:
	print 2 * a - 1
elif a == b:
	print 2 * a
else:
	print 2 * b - 1