import java.util.Vector;
import java.lang.Boolean;
import java.lang.Object;

class Pair<U, T> {
    U a;
    T b;

    make(x) {
		var ret = new Pair<>();
		ret.a = x.elementAt(0);
		ret.b = x.elementAt(1);
		return ret;
    }
 /*
    eq(a, b) {
    	b = a;
    	return a == b;
    }

    compare( p) {
		return  eq(p.a, p.b);
		//return p.a == p.b;
    }

    void m(Pair<?, ?> p, List<? extends Eq> b)
    {
	//this.compare(p); //1, type incorrect
	this.compare(this.make(b)); //2, OK
    }
*/
}