public class Pair<A extends Comparable, B extends Comparable> implements Comparable<Pair<A, B>>
{
    A a;
    B b;

    @Override
    public int compareTo(Pair<A, B> p)
    {
        if (a.equals(p.a))
            return b.compareTo(p.b);
        return a.compareTo(p.a);
    }

    @Override
    public boolean equals(Object o)
    {
        return o instanceof Pair && ((Pair) o).a.equals(a) && ((Pair) o).b.equals(b);
    }

    @Override
    public int hashCode()
    {
        return a.hashCode() ^ b.hashCode();
    }

    @Override
    public String toString()
    {
        return "(" + a.toString() + ", " + b.toString() + ")";
    }
}