Node Reverse(Node head) {
    if(head == null)
        return null;
    if(head.next == null)
        return head;
    Node temp = null; 
    Node current = head;
    while(current != null){

        temp = current.prev;
        current.prev = current.next; 
        current.next = temp; 
        current = current.prev;
        
    }
    if(temp!=null)
        head = temp.prev;
    return head;
    
}