-al a-a a-b aaa aab aaf aal aan ab- aba abb abf abl abn af- afa afb aff afl afn al- ala alb alf all aln an- ana anb anf anl ann baa bab baf bal ban bba bbb bbf bbl bbn bfa bfb bff bfl bfn bla blb blf bll bln bna bnb bnf bnl bnn faa fab faf fal fan fba fbb fbf fbl fbn ffa fff ffl ffn fla flb flf fll fln fna fnb fnf fnl fnn la- laa lab laf lal lan lba lbb lbf lbl lfa lfb lff lfl lfn lla llb llf lll lln lna lnb lnl lnn naa nab naf nal nan nba nbb nbf nbl nbn nfa nfb nff nfl nfn nla nlb nlf nll nln nna nnb nnf nnl nnn