a-ak aaaa aaab aaba aabb aabt aaka aata aatk aatt abaa abab abak abat abb- abba abbb abbt abta akaa akka at-t ataa atab atak atat atka atkt atta baaa baak baat baba babb bak- baka bakt bata batt bbbb btaa bttb kaaa kaab kaak kaat kaba kabb kaka kakk kakt kat- kata katb katk katt kbaa kbab kbak kbat kbba kbbb kbbk kbbt kbkb kbkk kbta kbtb kbtk kbtt kkaa kkat kkba kkbb kkbt kkkk kktk ktaa ktak ktat ktba ktbb ktbt ktkb ktkk ktkt kttk kttt taa- taat taba tabb taka takk takt tata tatb tatt tbta ttab ttbb tttt