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 Pascal (FPC 2.6.2) (judge verdict: Wrong Answer)

type ary=array[1..100001]of char;
var a,b,i,j  :integer;
    c:char;
    l  :ary;
    
begin
  j:=1; a:=0; b:=0;
  for i:=1 to 100001 do 
    if i mod 2 = 0 then l[i]:='0'
    else l[i]:='1';
  repeat
    read(c);
    if c=l[j] then inc(a)
    else inc(b);
    inc(j)
  until eoln ;
  if a<b then write(a) 
  else write(b)
  end.