1
X-------------------X------X--------------------X
X                   X      X                    X
X   1               X  F   -  X       a    4    X
X                   X         X                 X
X                   X         X                 X
X--------X     X-----------------------X        X
X        X     X                       X   a    X
X        X     X                       X        X
X        X     X                       X        X
X        -     -              a        X        X
X                                      -        X
X                   a                           X
X                                               X
X        X                             X--------X
X        X                             X        X
X        X                             X        X
X    R   X                             X        X
X        X      A      A  2   A     A  X   B    X
X        X                             X        X
X        X                             X        X
X        X                    a        X        X
X---------X                            -        X
X         X       a                             X
X         X                                     X
X         X                                     X
X         X                X  X                 X
X         --------         X  X                 X
X                          X  ------------------X
X                          X                    X
X              X-----------X                    X
X              X           X                    X
X  a           X           X                    X
X              X           X                    X
X    5         -   X    F  X              1     X
X       a          X       X                    X
X                  X       X                    X
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