#include <iostream>

using namespace std;

template<class T>
struct Node
{
    T data;
    Node* next=nullptr;
};

template<class T>
class Stack
{
private:
    Node<T>* first=nullptr;
public:
    void add_element(T data)
    {
        if(first==nullptr)
        {
            Node<T>* a = new Node<T>;
            a->data=data;
            first=a;
        }
        else
        {
            Node<T>* current=first;
            while(current->next!=nullptr)
            {
                current=current->next;
            }
            Node<T>* a = new Node<T>;
            a->data=data;
            current->next=a;
        }
    }
    T peak()
    {
        Node<T>* current=first;
        while(current->next!=nullptr)
        {
            current=current->next;
        }
        return current->data;
    }
    void pop()
    {
        Node<T>* current=first;
        if(current->next==nullptr)
        {
            delete current->next;
            current->next=nullptr;
        }
        else
        {
            while(current->next->next!=nullptr)
            {
                current=current->next;
            }
            delete current->next;
            current->next=nullptr;
        }
    }
    void print()
    {
        Node<T>* current=first;
        while(current!=nullptr)
        {
            cout<<current->data;
            current=current->next;
        }
    }

};

int main()
{
    Stack<char> s;
    s.add_element('(');
    s.add_element(')');
    s.print();
    cout<<s.peak();
    s.pop();
    s.print();
    return 0;
}