#include <cstring>
#include <optional>
using namespace std;

const int A = 4;
const int B = 6;
const int CD = 8;
const int E = 6;

optional<int> fa(int a)
{
    if (a >= A) {
        return a/2;
    } else {
        return nullopt;
    }
}

optional<int> fb(int b)
{
    if (b >= B) {
        return b/3;
    } else {
        return nullopt;
    }
}

optional<int> fcd(int c, int d)
{
    if (c*d >= CD) {
        return c*d/2;
    } else {
        return nullopt;
    }
}

optional<int> fe(int e)
{
    if (e >= E) {
        return e;
    } else {
        return nullopt;
    }
}
 
int main(int argc, char *argv[])
{
    int a = atoi(argv[1]);
    int b = atoi(argv[2]);

    if (optional<int> tmp, x;
        (tmp = fa(a)) && (x = fb(b)) && (x = fcd(*tmp, *x)) && (x = fe(*x)))
    {
        return *x;
    } else {
        return 0;
    }
}