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>
int main(void){
  int n=0;
  char S[100000];
  char *p1=&S[0];
  char *p2=&S[1];
  
  scanf("%s",&S);
  
  while(*p2!='\0'){
    if((*p1==*p2) && (*p2=='0')){
      n++;
      *p2='1';
    }
    if((*p1==*p2) && (*p2=='1')){
      n++;
      *p2='0';
    }
    p1++; p2++;
  }
  printf("%d\n",n);
  return 0;
}