30 50 CABBAADAAAAAAAAAAAAAAAAAAAA CDCAABAAAAAAAAAAAAAAAAAAAAA CAADABDAAAAAAAAAAAAAAAAAAAA A A A B B C AA AA AA AA AA AA AB AB AB AC AC BB BB BB BB BB BC BC CC CC CC AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAB AAB AAB AAB AAC AAC AAC ABB ABB ABB BCADAAAAACAAAAAAAAAAAAAAAAA DCDBAAAAAAAAAAAAAAAAAAAAAAA ACDBAABAAAAAAAAAAAAAAAAAAAA B C D C D D BB BC BD CC CD DD CC CD DD BD DD AC AD CC CD DD AD DD AD BD DD BBB BBC BBD BCC BCD BDD CCC CCD CDD DDD CCC CCD CDD DDD BBD BDD DDD CCC CCD CDD