public int positionOfLastFiveFromEnd () {
    return positionOfLastFiveFromEndHelper (first);
}
 private static int positionOfLastFiveFromEndHelper(Node i) {
    if (i == null) return -1;
    int result = positionOfLastFiveFromEndHelper(i.next);
    result = result -1;
    if (i.item == 5)
    //ans = ans +1;
    //return ans;
    return result;