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: Wrong Answer)

#include <stdio.h>
#include <string.h>

int main(){
  char S[100000] = {}; scanf("%s", &S);
  int length = strlen(S);
  /* int ans = sizeof(S); */
  int i, j, count, ans;

  for(i = 0; i < 2; i++){
    count = 0;
    for(j = 0; j < length; j++){
      if(j % 2 == 0 && S[j] != (char)(i + '0')) count++;
      if(j % 2 == 1 && S[j] == (char)(i + '0')) count++;
    }
    if(i == 0)ans = count;
  }

  ans = (ans < count ? ans : count);
  
  printf("%d\n", ans);

  return 0;
}