a-a a-b a-c aaa aab aac aae aao aap ab- aba abb abc abe abo abp ac- aca acb acc ace aco acp aea aeb aec aee aeo aep aoa aob aoc aoe aoo aop ap- apa apb apc ape apo app b-p baa bab bac bae bao bap bba bbb bbc bbe bbo bbp bca bcb bcc bce bco bcp be- bea beb bec bee beo bep boa bob boc boe boo bop bpa bpb bpc bpe bpo bpp c-- caa cab cac cae cao cap cba cbb cbc cbe cbo cbp cca ccb ccc cce cco ccp ce- cea ceb cec cee ceo cep co- coa cob coc coe coo cop cpa cpb cpc cpe cpo cpp eaa eab eac eae eao eap eba ebb ebc ebe ebo ebp ec- eca ecb ecc ece eco eea eeb eec eee eeo eep eo- eoa eob eoc eoe eoo eop ep- epa epb epc epe epo epp oaa oab oac oae oao oap ob- oba obb obc obe obo obp oc- oca ocb occ oco ocp oea oeb oec oee oeo oep oo- ooa oob ooc ooo oop op- opa opb opc ope opo opp p-p paa pab pac pae pao pap pba pbb pbc pbe pbo pbp pca pcb pcc pce pco pcp pea peb pec pee peo pep poa pob poc poe poo pop ppa ppb ppc ppe ppo ppp