template<typename S>
class Level {
public:
	S item;
	Level* next;
	Level(S it, Level* stk) {
		item = it;
		next = stk;
	}
	~Level() {
		delete next;
	}
};

template<typename T>
class Stack {
public:
	Level<T>* top;
	Stack() {
		top = NULL;
	}
	void push(T item) {
		top = new Level<T>(item, top);
	}
	T pop() {
		T item = top->item;
		this->top = top->next;
		return item;
	}
	~Stack() {
		delete top;
	}
};