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++14 (GCC 5.4.1) (judge verdict: Accepted)

// header {{{
#include <bits/stdc++.h>
using namespace std;

// {U}{INT,LONG,LLONG}_{MAX,MIN}
#define INF         INT_MAX/3
#define LLINF       LLONG_MAX/3
#define MOD         (1000000007LL)
#define MODA(a, b)  a=((a)+(b))%MOD
#define MODP(a, b)  a=((a)*(b))%MOD
#define inc(i, l, r)   for(int i=(l);i<(r);i++)
#define dec(i, l, r)   for(int i=(r)-1;i>=(l);i--)
#define pb          push_back
#define se          second
#define fi          first
#define mset(a, b)  memset(a, b, sizeof(a))

using LL  = long long;
using G   = vector<vector<int>>;

int di[] = {0, -1, 0, 1};
int dj[] = {1, 0, -1, 0};
// }}}

int main() {
    cin.tie(0);ios::sync_with_stdio(false);
    int a, b;cin >> a >> b;
    cout << max({a+b, a+a-1, b+b-1}) << endl;
    return 0;
}