class CQueue {

    private int[] queue;
    private int head;
    private int tail;
    private int capacity;

    public CQueue() {
        capacity = 10000;
        queue = new int[capacity];
        tail = 1;
        head = 0;
    }
    
    public void appendTail(int value) {
        queue[((tail++ - 1) % capacity)] = value;
    }
    
    public int deleteHead() {
        if ((head + 1 % capacity) == tail) return -1;
        return queue[head++ % capacity];
    }
}