a-a a-b a-z aaa aab aap aas aaz ab- aba abb abp abs abz ap- apa apb app aps as- asa asb asp ass asz az- aza azb azp azs azz b-p baa bab bap bas baz bba bbb bbp bbs bpa bpb bpp bps bsa bsb bsp bss bza bzp bzs bzz p-p paa pab pap pas paz pba pbb pbp pbs pbz ppa ppb ppp pps ppz ps- psa psb psp pss pzp saa sab sap sas saz sba sbb sbp sbs spa spb spp sps spz ss- ssa ssb ssp sss ssz sza szp zaa zab zap zas zaz zbb zbs zpp zsa zsz zzs zzz