first_employee = int(input())
second_employee = int(input())
third_employee = int(input())
number_of_students = int(input())

hours = 0

students_per_hour = first_employee + second_employee + third_employee

while number_of_students > 0:
    hours += 1
    if hours % 4 != 0:
        number_of_students -= students_per_hour
    if hours % 4 == 0:
        pass


print(f"Time needed: {hours}h.")