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
#!/usr/bin/python
# -*- Coding: utf-8 -*-

def main():
    buttons = raw_input()
    buttons = buttons.split()
    ans = 0
    cnt = 0
    A = int(buttons[0])
    B = int(buttons[1])
    while cnt < 2:
        if A > B:
            ans += A
            A = A - 1
        elif A < B:
            ans += B
            B = B - 1
        elif A == B:
            ans += A
            A = A - 1
        cnt += 1
    print(ans)
main()
