def convert_timetable(start, end):
    """
    Function to convert rows to time
    :param start: Starting row number
    :param end: Ending row number
    :return: Tuple with all correct starting and ending times
    """

    timetable = {
        1: ("8:30", "9:20"),
        2: ("9:20", "10:10"),
        3: ("10:30", "11:20"),
        4: ("11:20", "12:10"),
        5: ("12:10", "13:00"),
        6: ("13:00", "13:50"),
        7: ("13:50", "14:40"),
        8: ("15:00", "15:50"),
        9: ("15:50", "16:40"),
        10: ("17:00", "17:50"),
        11: ("17:50", "18:40"),
        12: ("18:40", "19:30"),
        13: ("19:30", "20:20"),
        14: ("20:20", "21:10"),
        15: ("21:10", "22:00"),
    }

    start_begin = timetable[start][0]
    start_end = timetable[start][1]
    end_begin = timetable[end][0]
    end_end = timetable[end][1]

    return start_begin, start_end, end_begin, end_end