-ic a-a a-b a-c a-i aaa aab aac aai aao aap aas ab- aba abb abc abi abo abp abs ac- aca acb acc aci aco acp acs ai- aia aib aic aii aio aip ais aoa aob aoc aoi aoo aop aos ap- apa apb apc api apo app aps as- asa asb asc asi aso asp ass b-p baa bab bac bai bao bap bas bba bbb bbc bbi bbo bbp bbs bca bcb bcc bci bco bcp bcs bi- bia bib bic bii bio bip bis boa bob boc boi boo bop bos bpa bpb bpc bpi bpo bpp bps bsa bsb bsc bsi bso bsp bss c-- caa cab cac cai cao cap cas cba cbb cbc cbi cbo cbp cbs cca ccb ccc cci cco ccp ccs ci- cia cib cic cii cio cip cis co- coa cob coc coi coo cop cos cpa cpb cpc cpi cpo cpp cps csa csb csc csi cso csp css ia- iaa iab iac iai iao iap ias iba ibb ibc ibi ibo ibp ibs ica icb icc ici ico icp ics iia iib iic iii iio iip iis io- ioa iob ioc ioi ioo iop ios ipa ipb ipc ipi ipo ipp ips is- isa isb isc isi iso isp iss o-i oaa oab oac oai oao oap oas ob- oba obb obc obi obo obp obs oc- oca ocb occ oci oco ocp ocs oia oib oic oii oio oip ois oo- ooa oob ooc ooi ooo oop oos op- opa opb opc opi opo opp ops os- osa osb osc osi oso osp oss p-p paa pab pac pai pao pap pas pba pbb pbc pbi pbo pbp pbs pca pcb pcc pci pco pcp pcs pia pib pic pii pio pip pis poa pob poc poi poo pop pos ppa ppb ppc ppi ppo ppp pps ps- psa psb psc psi pso psp pss saa sab sac sai sao sap sas sba sbb sbc sbi sbo sbp sbs sca scb scc sci sco scp scs sia sib sic sii sio sip sis soa sob soc soi soo sop sos spa spb spc spi spo spp sps ss- ssa ssb ssc ssi sso ssp sss