6        
                
                
                                              4       
                                                      
                                                      
                                                          p/2        
                                                                     
                                                                     

   

   

   

   

   

   

   

   

   

   

                                                                                      

                                                                                             

                                                                            o      
                                                                                   
                                                                                   

   

   

   

   

   

   1