class Poly {
    public String greeting() { return "Hello"; }
}
public class List<T> {
    public T info; 
    public List<T> next;
    public List (T x, List<T> l) {
       info = x; 
       next = l;
    }
    public void insert(T x) {
       next = new List<T> (x, next);
    }
    public void delete() {
       if (next != null) next = next.next;
    }
    public static void main (String [] args) {
        List<Poly> list 
               = new List<Poly> (new Poly(), null);
        System.out.println(list.info.greeting());
    }
} // end of class List