public class Node 
{
    private int v;
    private Node next;

    public Node(int n)
    {
	v = n;
    }

    public Node()
    {
	this(0);
    }

    int readnumber()
    {
	return v;
    }
    void writenumber(int nr)
    {
	v = nr;
    }
    Node successor()
    {
	return next;
    }
    void writesucc(Node nextnode)
    {
	next = nextnode;
    }
}