interface KEY {
    boolean less(KEY k); // binary method
    boolean equals(KEY k); // binary method
}

interface ITEM {
    KEY key ();
}

class myKey implements KEY {
    private int val;
    static int M = 1000000;

    public boolean less (KEY k) {
	return val < ((myKey) k).val;
    }
    public boolean equals (KEY k) {
	return val == ((myKey) k).val;
    }
    void read () { val = In.getInt (); }
    void rand () { val = (int) (M * Math.random ()); }
    public String toString () { return val + ""; }
}

class myItem implements ITEM {
    private myKey val;
    private double info;

    myItem() { val = new myKey (); }
    public KEY key () { return val; }
    void read () {
	val.read (); info = In.getDouble ();
    }
    void rand () {
	val.rand (); info = (double) Math.random ();
    }
    public String toString () {
	return "(" + key () + " " + info + ")";
    }
}

public class SymbolTable {

    private class Node {
	ITEM item;
	Node l, r;
	Node (ITEM x) { item = x; }
    }

    private boolean item_less (ITEM i1, ITEM i2) {
	return (i1.key ()).less(i2.key ());
    }

    private boolean item_equals (ITEM i1, ITEM i2) {
	return (i1.key ()).equals(i2.key ());
    }

    private Node head;

    SymbolTable (int maxN) {
	head = null;
    }

    private Node insertR(Node h, ITEM x) {
	if (null == h) return new Node (x);

	if (item_less(x, h.item))
	    h.l = insertR (h.l, x);
	else
	    h.r = insertR (h.r, x);

	return h;
    }

    void insert (ITEM x) {
	head = insertR (head, x);
    }

    private ITEM searchR(Node h, KEY k) {
	if (null == h) return null;
	if (k.equals(h.item.key())) return h.item;
	if (k.less(h.item.key()))
	    return searchR (h.l, k);
	else
	    return searchR (h.r, k);
    }

    ITEM search (KEY k) { return searchR (head, k); }

}