def get_announcement(message, reminder_offset):
    """
    Generates the announcement message

    :param str message: Message about the event
    :param number reminder_offset: Minutes in which event is about to happen
    """

    pos = message.find(":")
    if pos == -1:
        activity = message.strip()
        message = f"{activity} in {reminder_offset} minutes."
    else:
        activity = message[pos + 1 :].strip()
        person = message[0:pos].strip()
        message = f"Hello {person}, you have {activity} in {reminder_offset} minutes."

    return message