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 = 0, B = 0, X = 0, i;
    while(1){
        scanf("%d %d", &A, &B);
        if(3<=A && B<=20){
            break;
        }else{
            printf("plese set number");
        }
    }
    for(i=0; i<2; i++){
        if(A >= B){
            X = X + A;
            A = A - 1;
        }else if(A < B){
            X = X + B;
            B = B - 1;
        }
    }
    printf("%d", X);
}