a-a a-b aaa aab aae aak aap ab- aba abb abe abk abp aea aeb aee aek aep aka akb ake akk akp ap- apa apb ape apk app b-p baa bab bae bak bap bba bbb bbe bbk bbp be- bea beb bee bek bep bka bkb bke bkk bkp bpa bpb bpe bpp eaa eab eae eak eap eba ebb ebe ebk ebp eea eeb eee eek eep eka ekb eke ekp ep- epa epb epe epp ka- kaa kab kae kak kap kba kbb kbe kbk kbp ke- kea keb kee kek kep kkb kke kkk kkp kpa kpe kpk kpp p-p paa pab pae pak pap pba pbb pbe pbk pbp pea peb pee pek pep pka pkb pke pkp ppa ppb ppe ppk ppp