a     
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                                                                                 0
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                                                                                 2
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                                      XYZ as xyz                                  
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                                RST as rst                                        
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                     UVW as uvw                                                   
                                                                                  
                                                                                  
                                                                                  
                                                                                  
                                                                                 b