a-a a-b a-i aaa aab aaf aai aan aar aas ab- aba abb abf abi abn abr abs af- afa afb aff afi afn afr afs ai- aia aib aif aii ain air ais an- ana anb anf ani ann anr ans ar- ara arb arf ari arn arr ars as- asa asb asf asi asn asr ass baa bab baf bai ban bar bas bba bbb bbf bbi bbn bbr bbs bfa bfb bff bfi bfn bfr bfs bi- bia bib bif bii bin bir bis bna bnb bnf bni bnn bnr bns bra brb brf bri brn brr brs bsa bsb bsf bsi bsn bsr bss faa fab faf fai fan far fas fba fbb fbf fbi fbn fbr fbs ffa fff ffi ffn ffr ffs fia fib fif fii fin fir fis fna fnb fnf fni fnn fnr fns fra frb frf fri frn frr frs fsa fsb fsf fsi fsn fsr fss i-f ia- iaa iab iaf iai ian iar ias iba ibb ibf ibi ibn ibr ibs ifa ifb iff ifi ifn ifr ifs iia iib iif iii iin iir iis in- ina inb inf ini inn inr ins ir- ira irb irf iri irn irr irs is- isa isb isf isi isn isr iss n-i naa nab naf nai nan nar nas nba nbb nbf nbi nbn nbr nbs nfa nfb nff nfi nfn nfr nfs nia nib nif nii nin nir nis nna nnb nnf nni nnn nns nra nrb nrf nri nrn nrr nrs nsa nsb nsf nsi nsn nsr nss ra- raa rab raf rai ran rar ras rba rbb rbf rbi rbn rbr rbs rfa rfb rff rfi rfn rfr rfs ria rib rif rii rin rir ris rna rnb rni rnn rnr rns rra rrb rrf rri rrn rrr rrs rsa rsb rsf rsi rsn rsr rss saa sab saf sai san sar sas sba sbb sbf sbi sbn sbr sbs sfa sfb sff sfi sfn sfr sfs sia sib sif sii sin sir sis sna snb snf sni snn snr sns sr- sra srb srf sri srn srr srs ss- ssa ssb ssf ssi ssn ssr sss