                                                       
     2            2                                               3                            
     3       60     15                                                  3                        
       7       1.                              2.        120  140               5.5  6     3.             70%     120  140            4.                            5.                             6.                       800        7.      3  5   5000  8000                       4                           
        8         1.                          2.                                             3.                        4.                           5.                    6.                            7.                     8                                           