#include <iostream>

using namespace std;

template<class T>
class Queue
{
    int head;
    int tail;
    T * array;
    void copyQueue(const Queue<T>& other)
    {
        head = other.head;
        tail = other.tail;
        array = new T[tail - head + 1];
        for(int i = other.head; i <= other.tail; i++)
            array[i] = other.array[i];
    }
    void removeQueue()
    {
        if(array != nullptr)
            delete[] array;
    }
public:
    Queue<T>() //default constructor
    {
        head = 0;
        tail = -1;
    }
    Queue<T>(const Queue<T>& other) //copy constructor
    {
        copyQueue(other);
    }
    Queue<T>& operator=(const Queue<T>& other) //copy assignment operator
    {
        if(this != &other)
        {
            removeQueue();
            copyQueue(other);
        }
        return *this;
    }
    ~Queue<T>() //destructor
    {
        removeQueue();
    }
    bool isEmpty() const
    {
        return head > tail;
    }
    int size() const
    {
        return tail - head + 1;
    }
    T front() const
    {
        return array[head];
    }
    T back() const
    {
        return array[tail];
    }
    void pop()
    {
        for (int i = head; i <= tail; i++)
        {
            array[i-1] = array[i];
        }
    }
    void push(T element)
    {
        array[++tail] = element;
    }
    void swap(int first, int second)
    {
        if(first!=second && first>=0 && second>=0)
        {
            T temp = array[first];
            array[first] = array[second];
            array[second] = temp;
        }
    }
    void swapQueue(Queue<T>& other)
    {
        Queue temp = *this;
        *this = other;
        other = temp;
        temp.removeQueue();
    }
    friend ostream& operator<<(ostream& os, const Queue<T>& q)
    {
        if(!q.isEmpty())
        {
            os << "Front position: " << q.head << "\nEnd position: " << q.tail << endl;
            for(int i = q.head; i <= q.tail; i++)
                os << q.array[i] << " ";
            os << endl;
        }
        else os << "Empty queue!";
        return os;
    }
    friend istream& operator>>(istream& is, Queue<T>& q)
    {
        is >> q.head >> q.tail;
        for(int i = q.head; i <= q.tail; i++)
            is >> q.array[i];
        return is;
    }
};

int main()
{
    Queue<int> q1;
    cin >> q1;
    cout << q1;
    return 0;
}