30 50
D C B DA CD CC CB CA BD BC BB BA AD AC AB DAA CDD CDC CDB CDA CCD CCC CCB CCA CBD CBC CBB CBA CAD CAC CAB CAA BDD BDC BDB BDA BCD BCC BCB BCA BBD BBC BBB BBA BAD BAC BAB BAA ADD ADC 
C B A CD CC CB CA BD BC BB BA AD AC AB AA CDD CDC CDB CDA CCD CCC CCB CCA CBD CBC CBB CBA CAD CAC CAB CAA BDD BDC BDB BDA BCD BCC BCB BCA BBD BBC BBB BBA BAD BAC BAB BAA ADD ADC ADB