#include <iostream>

using namespace std;


template <typename TElement>
class Sequence {
protected:
    int length;
    bool isEmpty;
public:
    Sequence();
    ~Sequence();
    virtual TElement Get (int index) = 0;
    virtual TElement GetFirst() = 0;
    virtual TElement GetLast () = 0;
    virtual Sequence<TElement> GetSubsequence (int startIndex, int endIndex) = 0;
    virtual void Append (TElement item) = 0;
    virtual void Prepend (TElement item) = 0;
    virtual void InsertAt (int index, TElement item) = 0;
    virtual void Remove (TElement item) = 0;

};

template <typename TElement>
class ArraySequence : Sequence<TElement> {
private:
    TElement *Array;
public:
    ArraySequence();
    ~ArraySequence();
    TElement Get (int index);
    TElement GetFirst();
    TElement GetLast ();
    Sequence<TElement> GetSubsequence (int startIndex, int endIndex);
    void Append (TElement item);
    void Prepend (TElement item);
    void InsertAt (int index, TElement item);
    void Remove (TElement item);
};

template <typename TElement>
ArraySequence<TElement>::ArraySequence() {
    Array = new TElement;
}

template <typename TElement>
ArraySequence<TElement>::~ArraySequence() {
    delete [] Array;
}

template <typename TElement>
TElement ArraySequence<TElement>:: Get (int index) {
    return Array[index];
}

template <typename TElement>
TElement ArraySequence<TElement>:: GetFirst () {
    return Array[0];
}