from typing import Tuple
from datetime import datetime


def getStartDatetime(start: str, days: Tuple) -> datetime:
    """ obtain starting datetime from json input

    :param start: string representation of the day and time
    :param days: a tuple of 3 characters representation of day

    :return : datetime instance
    """
    day, time = start.split(' ')
    day = days.index(day.lower())
    hour, minute = int(time[:2]), int(time[2:])
    return datetime(1, 1, day, hour, minute, 0, 0)