Problem:
Score : 100 points

Problem Statement

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.

Sample Input 1

5 3

Sample Output 1

9

You can get 5 + 4 = 9 coins by pressing the button of size 5 twice, and this is the maximum result.

Sample Input 2

3 4

Sample Output 2

7

Sample Input 3

6 6

Sample Output 3

12

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

int main() {

    int A ,B ,i;
    int res = 0;
    
    //空白区切りで入力
    scanf("%d %d" ,&A ,&B);

    for( i = 0; i < 2; i++)
    {
        if (A <= B) {
            res = res + B;
            B--;
        }else if (B <= A)
        {
            res = res + A;
            A--;
        }
    }
    
    printf("%d\n" ,res);

    return 0;

}