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)
{
	char s[100001];
	int count=0;
	
	scanf("%s",s);
	
	for(int i=1;s[i]!='\0';i++){
		
		if(s[i-1]==s[i]){
			
			if(s[i-1]=='0'){
				
				s[i]='1';
				
			}else{
				
				s[i]='0';
				
			}
			
			count++;
			
		}
	}
	
	printf("%d\n",count);
	
	return 0;
}