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?

Input

Input is given from Standard Input in the following format:
A B

Output

Print the maximum number of coins you can get.

Constraints

• All values in input are integers.
• $3 \leq A, B \leq 20$

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

见题面 Input 部分

见题面 Output 部分