30 50
DBB B DD DDC DD DCB DB CC DCC DC DDC DD D DC CC DDD DDB DDD DDB DDD DDD DC DDC BB BB DCC DD DDD CB DDD DDD DDC DDD BB DD DB DD D DDD CB DDB D DDD CC DCC C CC CC DCC C 
CCA A CA AAA BB AAA AA BA BBB BA BAA CB B AA DA BBA AAA CCA CCA CBB CCB BB BBA CA AA AAA AA AAA DA BAA CBA BBB CAA DA BA CA CC A BBB AA CAA C CCC AA BAA A BB DB BBA B