.
                                   N o
                           -b    N o      -b
                          r       N o          r
                        a           N             a
                       i             o                i
                      n             N                n
                     e              o                   e
                     r           N      o              r
                    -b          N        o           -b
                     r           N       o             r
                      a            N   o             a
                       i              N               i
                         n           o             n
                            e         N          e
                                r      o      r