#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main()
{
    int a, b;
    cin >> a >> b;
    int ans = 0;
    if(a < b){
        b--;
        while(true){
            if(a == 0) break;
            a--; ans++;
            if(b == 0) break;
            b--; ans++;
        }
    }
    else{
        a--;
        while(true){
            if(b == 0) break;
            b--; ans++;
            if(a == 0) break;
            a--; ans++;
        }
    }
    cout << ans << endl;
    return 0;
}