 1
                                    
                                
                                1 
                             
                                                                  
                                
                               
                                         2-3
                                                                 
                                                               
                                2-3 
                             
                                                                  
                                
                               
                                         4-5
                                                                 
                                                               
                                4-5 
                             
                                                                  
                                
                               
                                         6-7
                                                                 
                                                               
                                6-7 
                             8-9
                                                                  
                                
                                                               
                                8-9 
                             1
                                1
                             
                                        