-al a-a a-b a-c aaa aab aac aae aal ab- aba abb abc abe abl ac- aca acb acc ace acl aea aeb aec aee ael al- ala alb alc ale all baa bab bac bae bal bba bbb bbc bbe bbl bca bcb bcc bce bcl be- bea beb bec bee bel bla blb blc ble bll c-- caa cab cac cae cal cba cbb cbc cbe cbl cca ccb ccc cce ccl ce- cea ceb cec cee cel cl- cla clb clc cle cll eaa eab eac eae eal eba ebb ebc ebe ebl ec- eca ecb ecc ece ecl eea eeb eec eee eel ela elb elc ele ell la- laa lab lac lae lal lba lbb lbc lbe lbl lca lcb lcc lce lcl lea leb lec lee lel lla llb llc lle lll