p03071 AtCoder Beginner Contest 124 - Buttons_16111
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
#include<bits/stdc++.h>
using namespace std;

int main(){
	int a,b;
  cin >> a>>b;
  cout << max(max(b+b-1,a+a-1),a+b) <<endl;
  return 0;
}
