import datetime
class Room:
    def __init__(self, room_number, room_type, rate, availability=True):
        self.room_number = room_number
        self.room_type = room_type
        self.rate = rate
        self.availability = availability

class Reservation:
    def __init__(self, room, start_date, end_date):
        self.room = room
        self.start_date = start_date
        self.end_date = end_date
        self.total_cost = self.calculate_tatal_cost()

    def calculate_total_cost(self):
        days = (self.end_date - self.start_date).days
        return days * self.room.rate

class Hotel:
    def __init__(self, name):
        self.name = name
        self.rooms = []
        self.reservations = []