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
import java.util.Scanner;

public class Main {
	private static void p(String s) {System.out.println(s);}
	static Scanner sc = new Scanner(System.in);
	static int a,b,c,n,m;
	public static void main(String[] args) {
		a=sc.nextInt();
		b=sc.nextInt();
		int max=Math.max(a, b);
		int min=Math.min(a,b);
		int ans=max+Math.max(max-1, min);
		p(""+ans);
	}
}
