#include <iostream>
using namespace std;
long long n, m;
long long horiz, vertik;
long long answer = 0;
int main ()
{
    cin >> n >> m;
    //cout << n << endl;
    if(n > m)
    {
        int c;
        c = m;
        m = n;
        n = c;
    }
    horiz = (m / 2) + 2;
    if(horiz % 2 == 1) ++ horiz;
    vertik = n - (horiz / 2);
    //cout << m << " " << vertik << endl;
    //cout << horiz << " " << vertik << endl;
    if(m != horiz) {
    if (n - (horiz / 2) >= 0) 
    {
        answer += horiz;
        if( vertik / 2 <= m - horiz) {
            answer += (vertik/2) * 2;
        }
        else
        {
            if ((m - horiz)%2 == 1) answer += (m - horiz - 1) * 2;
            else answer += (m - horiz) * 2;
        }
    }
    else 
    { 
        answer += n * 2; 
    }
    cout << answer << endl;
    }
    else cout << horiz << endl;
    return 0;
}