                                                                              1990   04   17    ??      1 + 9 + 9 + 0 + 4 + 1 + 7 = 31.         3 + 1 = 4          4                  
? ???     ?? 
   1.                                                                                                               
    2.                                                                      
     3.                                                                           
    4.                                                                                         
 
   5.                                                 
   6.      ??                                              ? ?                   
   7.                              ??                                        
    8.                            ??                                     
    9.                                         ??                                            ??                             