using System;

namespace SoftuniRecepcion
{
    class Program
    {
        static void Main(string[] args)
        {
            int employee1 = int.Parse(Console.ReadLine());
            int employee2 = int.Parse(Console.ReadLine());
            int employee3 = int.Parse(Console.ReadLine());
            int students = int.Parse(Console.ReadLine());


            int studentsPerHour = employee1 + employee2 + employee3;
            if (studentsPerHour != 0)
            {
                double time = Math.Ceiling(students / (studentsPerHour * 1.00));
                if (time > 3)
                {
                    time = 4 * time / 3;
                }

                Console.WriteLine($"Time needed: {(int)time}h.");
            }
        }
    }
}