class Pair<T, U> {
	T x;
	U y;
	
	public Pair() { }
	public Pair(T x, U y) {
		this.x = x;
		this.y = y;
	}
	
	public T fst () {
		return x;
	}
	
	public U snd () { 
		return y;
    }
}