// has_a2 DIS
// a reference as an instance variable

class Person {
    int k;
    Person a;
    void print() {System.out.println(k);}
}

public class has_a2 {
    public static void main(String[] args) {
	
	Person x = new Person();
	Person y = new Person();
	x.k=1;
	y.k=2;
	x.a = y;
	y.a = x;
	
	x.print();
	y.print();
	x.a.print();
	y.a.print();
	x.a.a.print();
	y.a.a.print();
    }

}

/* output
1
2
2
1
1
2
*/