import datetime

# Placeholder appointment data
appointments = {}

def book_appointment(doctor: str, date: str, time: str):
    appointment_id = str(datetime.datetime.now().timestamp())[:10]
    appointments[appointment_id] = {
        "doctor": doctor,
        "date": date,
        "time": time,
        "status": "Booked"
    }
    return f"Your appointment with Dr. {doctor} has been booked for {date} at {time}. Appointment ID: {appointment_id}"

def cancel_appointment(appointment_id: str):
    if appointment_id in appointments:
        appointments[appointment_id]["status"] = "Cancelled"
        return f"Your appointment with {appointments[appointment_id]['doctor']} has been cancelled."
    return "Appointment not found."

def follow_up_appointment(appointment_id: str):
    if appointment_id in appointments:
        appointment = appointments[appointment_id]
        return f"Appointment with Dr. {appointment['doctor']} is scheduled for {appointment['date']} at {appointment['time']}. Status: {appointment['status']}"
    return "Appointment not found."