-ic a-a a-b a-c a-i aaa aab aac aaf aai aar aax ab- aba abb abc abf abi abr abx ac- aca acb acc acf aci acr acx af- afa afb afc aff afi afr afx ai- aia aib aic aif aii air aix ar- ara arb arc arf ari arr arx ax- axa axi axr axx baa bab bac baf bai bar bax bba bbb bbc bbf bbi bbr bbx bca bcb bcc bcf bci bcr bcx bfa bfb bfc bff bfi bfr bfx bi- bia bib bic bif bii bir bix bra brb brf bri brr brx bxb bxi bxx c-- caa cab cac caf cai car cax cba cbb cbc cbf cbi cbr cbx cca ccb ccc ccf cci ccr ccx cfa cfb cfc cff cfi cfr cfx ci- cia cib cic cif cii cir cix cra crb crc crf cri crr crx cxc cxf cxi cxr cxx faa fab fac faf fai far fax fba fbb fbc fbf fbi fbr fbx fca fcb fcc fcf fci fcr fcx ffa ffc fff ffi ffr ffx fia fib fic fif fii fir fix fra frb frc frf fri frr fxi fxr fxx i-f ia- iaa iab iac iaf iai iar iba ibb ibc ibf ibi ibr ibx ica icb icc icf ici icr ifa ifb ifc iff ifi ifr ifx iia iib iic iif iii iir iix ir- ira irb irc irf iri irr irx ixc ixi ra- raa rab rac raf rai rar rax rba rbb rbc rbf rbi rbr rbx rca rcb rcc rcf rci rcr rcx rfa rfb rfc rff rfi rfr ria rib ric rif rii rir rix rra rrb rrc rrf rri rrr rxr xaa xac xaf xar xbc xbr xbx xcb xcf xci xcr xcx xfa xfx xia xic xii xix xrc xrf xrx xxi xxx