public class MyStack {
private LinkedList link;
public MyStack() {
  link = new LinkedList();
}
public void add(Object obj) {
  link.addFirst(obj);
}
public Object get(int index) {
  return link.get(index);
}
public int size() {
  return link.size();
}
}

public class MyStack {
private LinkedList link;
public MyStack() {
  link = new LinkedList();
}
public void add(Object obj) {
  link.addFirst(obj);
}
public Object get(int index) {
  return link.get(index);
}
public int size() {
  return link.size();
}
}