a-a a-b aaa aab aae aak aan aap ab- aba abb abe abk abn abp aea aeb aee aek aen aep aka akb ake akk akn akp an- ana anb ane ank ann anp ap- apa apb ape apk apn app b-p baa bab bae bak ban bap bba bbb bbe bbk bbn bbp be- bea beb bee bek ben bep bka bkb bke bkk bkn bkp bna bnb bne bnk bnn bnp bpa bpb bpe bpn bpp eaa eab eae eak ean eap eba ebb ebe ebk ebn ebp eea eeb eee eek een eep eka ekb eke ekp en- ena enb ene enk enn enp ep- epa epb epe epn epp ka- kaa kab kae kak kan kap kba kbb kbe kbk kbn kbp ke- kea keb kee kek ken kep kkb kke kkk kkn kkp kn- kna kne knk knn knp kpa kpe kpk kpn kpp naa nab nae nak nan nap nba nbb nbe nbk nbn nbp ne- nea neb nee nek nen nep nka nke nkk nkn nkp nna nnb nne nnk nnn nnp npa npb npe npn npp p-p paa pab pae pak pan pap pba pbb pbe pbk pbn pbp pea peb pee pek pen pep pka pkb pke pkn pkp pn- pna pnb pne pnk pnn pnp ppa ppb ppe ppk ppn ppp