a-a a-c a-t aaa aac aao aap aas aat ac- aca acc aco acp acs act aoa aoc aoo aop aos aot ap- apa apc apo app aps apt as- asa asc aso asp ass ast at- ata atc ato atp ats att c-- caa cac cao cap cas cat cca ccc cco ccp ccs cct co- coa coc coo cop cos cot cpa cpc cpo cpp cps cpt csa csc cso csp css cst cta ctc cto ctp cts ctt oaa oac oao oap oas oat oc- oca occ oco ocp ocs oct oo- ooa ooc ooo oop oos oot op- opa opc opo opp ops opt os- osa osc oso osp oss ost ot- ota otc oto otp ots ott p-p paa pac pao pap pas pat pca pcc pco pcp pcs pct poa poc poo pop pos pot ppa ppc ppo ppp pps ppt ps- psa psc pso psp pss pst pt- pta ptc pto ptp pts ptt saa sac sao sap sas sat sca scc sco scp scs sct soa soc soo sop sos sot spa spc spo spp sps spt ss- ssa ssc sso ssp sss sst sta stc sto stp sts stt taa tac tao tap tas tat tca tcc tco tcp tcs tct to- toa toc too top tos tot tpa tpc tpo tpp tps tpt tsa tsc tso tsp tss tst tta ttc tto ttp tts ttt