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 Python (3.4.3) (judge verdict: Runtime Error)

N, K = (input().split())
N=int(N)
K=int(K)
S = list(input())

tmpu = []

count = 0
onecount = 0
for i in S:
    if i == '0':
        count += 1
    if i == '1':
        tmpu.append(count)
        count=0
        onecount += 1


tmpu=tmpu.sort(reverse=True)

for n in range(K):
    onecount += tmpu[n]

print(onecount)