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 count(char *s) {
	int l = strlen(s);
	int e0 = 0, o0 = 0, e1 = 0, o1 = 0;
	int c1, c2;
	for (int i = 0; i < l; i += 2) if (s[i] != '0') e0++;
	for (int i = 0; i < l; i += 2) if (s[i] != '1') e1++;
	for (int i = 1; i < l; i += 2) if (s[i] != '1') o1++;
	for (int i = 1; i < l; i += 2) if (s[i] != '0') o0++;

	c1 = e0 + o1;
	c2 = e1 + o0;

	if (c1 < c2) return c1;
	return c2;
}

int main(int argc, char **argv) {
	char buff[1024];

	int r = scanf("%s", buff);
	//printf("%d\n", count(buff));
	printf("%d", count(buff));
	return 0;
}