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.

Examples

Input

5 3


Output

9


Input

3 4


Output

7


Input

6 6


Output

12
ar = []                                            
raw = raw_input().split()                          
#ar.append(int(raw))                               
#raw = raw_input()                                 
#raw = raw_input()                                 
#ar.append(int(raw))                               
#raw = raw_input()                                 
#ar.append(int(raw))                               
#raw = raw_input()                                 
#ar.append(int(raw))                               
#raw = raw_input()                                 
#ar.append(int(raw))                               




#n = ar[0]                                         
a = int(raw[0])                                    
b = int(raw[1])
#c = ar[3]
#d = ar[4]
#e = ar[5]                                         

first = max(a,b)                                   

if ( a > b):                                       
    a -= 1                                         
else:
    b -= 1                                         


second = max(a,b)                                  

print first + second 