-er -ic a-a a-b a-c a-i aaa aab aac aae aaf aai aak aar ab- aba abb abc abe abf abi abk abr ac- aca acb acc ace acf aci ack acr aea aeb aec aee aef aei aek aer af- afa afb afc afe aff afi afk afr ai- aia aib aic aie aif aii aik air aka akb akc ake aki akk akr ar- ara arb arc are arf ari ark arr baa bab bac bae baf bai bak bar bba bbb bbc bbe bbf bbi bbk bbr bca bcb bcc bce bcf bci bck bcr be- bea beb bec bee bef bei bek ber bfa bfb bfc bfe bff bfi bfr bi- bia bib bic bie bif bii bik bir bka bkb bkc bke bkf bkk bkr bra brb bre brf bri brk brr c-- caa cab cac cae caf cai cak car cba cbb cbc cbe cbf cbi cbk cbr cca ccb ccc cce ccf cci cck ccr ce- cea ceb cec cee cef cei cek cer cfa cfb cfc cfe cff cfi cfk cfr ci- cia cib cic cie cif cii cik cir cka ckb ckc cki cra crb crc cre crf cri crk crr eaa eab eac eae eaf eai eak ear eba ebb ebc ebe ebf ebi ebk ebr ec- eca ecb ecc ece ecf eci eck ecr eea eeb eec eee eef eek eer ef- efa efb efc efe eff efi efr eia eib eic eie eif eii eik eir eka ekb ekc eke ekf eki ekr era erb erc ere erf eri erk err faa fab fac fae faf fai fak far fba fbb fbc fbe fbf fbi fbk fbr fca fcb fcc fce fcf fci fck fcr fea feb fec fee fef fei fek fer ffa ffc ffe fff ffi ffk ffr fia fib fic fie fif fii fik fir fka fkb fkc fkf fki fkk fra frb frc fre frf fri frk frr i-f ia- iaa iab iac iae iaf iai iar iba ibb ibc ibe ibf ibi ibk ibr ica icb icc ice icf ici ick icr ie- iea iec iee ief iei iek ier ifa ifb ifc ife iff ifi ifr iia iib iic iie iif iii iir ika ikb ikc ike ikf iki ikk ikr ir- ira irb irc ire irf iri irk irr ka- kaa kab kac kae kaf kai kak kar kba kbb kbc kbe kbf kbi kbk kbr kca kcb kcc kce kci kck kcr ke- kea keb kec kee kef kei kek ker kfa kfc kff kfi kia kib kic kie kif kii kik kir kkb kkc kke kki kkk kkr kra krc krf kri krk krr ra- raa rab rac rae raf rai rak rar rba rbb rbc rbe rbf rbi rbk rbr rca rcb rcc rce rcf rci rcr re- rea reb rec ree ref rei rek rer rfa rfb rfc rfe rff rfi rfk rfr ria rib ric rie rif rii rik rir rkb rkc rke rkf rkk rra rrb rrc rrf rri rrk rrr