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(void){
  int a, b, coin;

  scanf("%d %d", &a, &b);
  coin=0;
  if(a<b){
    coin+=b;
    b-=1;
    if(a<b){
      coin+=b;
      b-=1;
    }else{
      coin+=a;
      a-=1;
    }
  }else{
    coin+=a;
    a-=1;
    if(a<b){
      coin+=b;
      b-=1;
    }else{
      coin+=a;
      a-=1;
    }
  }
  printf("%d\n", coin);
  return 0;
}