class Customer {

    private int id;
    private int arrivalTime;
   
    public Customer(int id, int arrivalTime) {
        this.id = id;
        this.arrivalTime = arrivalTime;
    }
    
    public int getWaitingTime(int time) {
        return time - arrivalTime;
    }

    public String toString() {
        return "Customer: " + id;
    }
}