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()
{
	int sum_a = 0,sum_b = 0;
	char c[100010];
	char a,b;
	gets(c);
	if(strlen(c) < 2) printf("0");
	else{
		for(int i = 0;i < strlen(c);i++){
			if(i % 2 == 0){
				a = '0';
				b = '1';
			}
			else{
				a = '1';
				b = '0';
			}
			if(c[i] != a) sum_a++;
			if(c[i] != b) sum_b++;
		}
		if(sum_a <= sum_b) printf("%d",sum_a);
		else printf("%d",sum_b);
	}
	return 0;
}