import java.util.ArrayList;

import java.util.Iterator;

import java.util.ListIterator;

class myStack<E> {

ArrayList<E> stack = new ArrayList<E>();

public int getsize(){

return stack.size();

}

public boolean isEmpty(){

return stack.isEmpty();

}

public E peek(){

return stack.get(getsize()-1);

}

public void push(E o){

stack.add(o);

}

public E pop(){

E o = stack.get(getsize()-1);

stack.remove(getsize()-1);

return o;

}

public <E> void printlist(){

ListIterator<E> it = (ListIterator<E>) stack.listIterator(getsize());

while(it.hasPrevious()){

System.out.println(it.previous());

}

}

}

public class GenericStack{

public static void main(String[] args){

myStack<String> s = new myStack<String>();

s.push("Hello");

s.push("World");

s.push("This");

s.push("Program");

System.out.println("Number of Elements before:"+s.peek());

System.out.println("\n"+"Before pop------------------"+"\n");

s.printlist();

System.out.println("\n"+"After pop-----------------------"+s.pop()+"\n");

s.printlist();

System.out.println("Number of Elements after:"+s.peek());

}

}