Buttons

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

inputFormat

input are integers.

• 3 \leq A, B \leq 20

Input

Input is given from Standard Input in the following format:

A B

outputFormat

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

样例

3 4

7