#include "stdafx.h"
#include "iostream"
#include "conio.h"

using namespace std;
int main()
{
	int A, B, C, D;
	int N =0;
	cin >> A >> B >> C >> D;
	while ((A || B || C || D) >=0){
		A--;
		B-=3;
		C-=2;
		D--;
		N++;
	}
	cout << N;
	_getch();
}