def findMergeNode(head1, head2):
    l1, l2 = head1, head2
    dummy = {}
    while l1:
        dummy[id(l1)] = l1.data
        l1=l1.next
    while l2:
        if id(l2) in dummy:
            return dummy[id(l2)]
        else:
            l2=l2.next