martelodoveigola.cpp

#include <bits/stdc++.h>

using namespace std;

int main(){
    int d,g;
	cin >> d >> g;
	int ans = 0;
	
	for(int x = -100; x <= 100; x++) {
		int dl = d+x;
		int gl = g-4*x;
		
		ans = max(ans,min(dl/6,gl));
	}
	cout << ans << endl;

    return 0;
}