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
l = map(int, raw_input().split());
ans = 0;

if (l[0] == l[1]):
	ans = l[0] + l[1];

elif(l[0] > l[1]):
	if (l[0] == 1):
		ans = l[0];
	else:
		ans = l[0] + l[0] - 1;

else:
	if (l[1] == 1):
		ans = l[1];
	else:
		ans = l[1] + l[1] - 1;

print ans;