package name.panitz.prog2MI;
public class Li<A>{
    private A hd=null;
    private Li<A> tl=null;
    public Li(){}
    public Li(A hd,Li<A> tl){
	this.hd=hd;
	this.tl=tl;
    }
    public A head(){return hd;}
    public Li<A> tail(){return tl;}

    public boolean isEmpty(){
	return head()==null && tail()==null;
    }
}