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)

#include <bits/stdc++.h>
using namespace std;
 
#define REP(i, n) for (int i = (int)(0); i < (int)(n); ++i)
#define REPS(i, n) for (int i = (int)(1); i <= (int)(n); ++i)
#define RREP(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define RREPS(i, n) for (int i = ((int)(n)); i > 0; i--)
#define IREP(i, m, n) for (int i = (int)(m); i < (int)(n); ++i)
#define IREPS(i, m, n) for (int i = (int)(m); i <= (int)(n); ++i)
#define FOR(e, c) for (auto &e : c)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RVISORT(v) sort(v.begin(), v.end(), greater<int>());
#define ALL(v) v.begin(), v.end()
#define MP(n, m) make_pair(n, m);
#define COUT(d) cout<<std::setprecision(10)<<d<<endl;
#define CIN(n) getline(cin,n);
 
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using ll = long long;
using ul = unsigned long;
 
typedef long long ll;
 
template<class T, class C> void chmax(T& a, C b){ a>b?:a=b; }
template<class T, class C> void chmin(T& a, C b){ a<b?:a=b; }
 
const int mod=1e9+7;
 
 
void printv(VI& v){
  REP(i,v.size()) cout << v[i] << " ";
  cout << endl;
}
 
int vtotal(VI& v){
  int total=0;
  REP(i,v.size()) total+=v[i];
  return total;
}
 
int main()
{
  cin.tie( 0 );
  ios::sync_with_stdio( false );
	
  //init(); // mint初期化
 
  ll a,b;
  cin>>a>>b;
 
  ll ans=0;
  if(a>b){
    ans+=a;a--;
  }
  else{
    ans+=b;b--;
  }
  if(a>b)ans+=a;
  else ans+=b;
 
  cout<<ans<<endl;
 
  return 0;
}