a-a a-b aaa aab aae aak aao aap ab- aba abb abe abk abo abp aea aeb aee aek aeo aep aka akb ake akk ako akp aoa aob aoe aok aoo aop ap- apa apb ape apk apo app b-p baa bab bae bak bao bap bba bbb bbe bbk bbo bbp be- bea beb bee bek beo bep bka bkb bke bkk bko bkp boa bob boe bok boo bop bpa bpb bpe bpo bpp eaa eab eae eak eao eap eba ebb ebe ebk ebo ebp eea eeb eee eek eeo eep eka ekb eke eko ekp eo- eoa eob eoe eok eoo eop ep- epa epb epe epo epp ka- kaa kab kae kak kao kap kba kbb kbe kbk kbo kbp ke- kea keb kee kek keo kep kkb kke kkk kkp koa kob koe kok koo kop kpa kpe kpk kpo kpp oaa oab oae oak oao oap ob- oba obb obe obk obo obp oea oeb oee oeo oep oka okb oke okk oko okp oo- ooa oob ook ooo oop op- opa opb ope opk opo opp p-p paa pab pae pak pao pap pba pbb pbe pbk pbo pbp pea peb pee pek peo pep pka pkb pke pko pkp poa pob poe pok poo pop ppa ppb ppe ppk ppo ppp