static int getLength(SinglyLinkedListNode node) {
        int length = 0;
        
        while (node != null) {
            node = node.next;
            length++;
        }
        
        return length;
    } 
     
    static int findMergeNode(SinglyLinkedListNode head1, SinglyLinkedListNode head2) {
        int length1 = getLength(head1);
        int length2 = getLength(head2);
        
        while (length1 > length2) {
            head1 = head1.next;
            length1--;
        }
        
        while (length2 > length1) {
            head2 = head2.next;
            length2--;
        }
        
        while (head1 != head2) {
            head1 = head1.next;
            head2 = head2.next;
        }
        
        return head1.data;
    }