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                         -             s            -
                         s            p             s
                       p             o               p
                      o               t                o
                      t            G     e            t
                      G          e   -   S           G
                       e           p    o             e
                        e              t                e
     ­                      -           G             -
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         ­                      p       e         p
                                 o     -        o
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                                         p
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                                         t