import java.util.*;

// This program is used to detect if the linklist is circular or not.

class DetectCircularLinkList {

static class Node {

int data;

Node next;

}

/*This function returns true if given linked

list is circular, else false. */

static boolean isCircular( Node head) {

if (head == null)

return true;

Node node = head.next;

while (node != null && node != head) {

node = node.next;

}

return (node == head);

}

static Node newNode(int data) {

Node temp = new Node();

temp.data = data;

temp.next = null;

return temp;

}

public static void main(String args[]) {

Node head = newNode(1);

head.next = newNode(2);

head.next.next = newNode(3);

head.next.next.next = newNode(4);

System.out.print(isCircular(head)? "Yes\n" :

"No\n" );

head.next.next.next.next = head;

System.out.print(isCircular(head)? "Yes\n" :

"No\n" );

}

}