a-a a-b a-i aaa aab aae aai aan aap ab- aba abb abe abi abn abp aea aeb aee aei aen aep ai- aia aib aie aii ain aip an- ana anb ane ani ann anp ap- apa apb ape api apn app b-p baa bab bae bai ban bap bba bbb bbe bbi bbn bbp be- bea beb bee bei ben bep bi- bia bib bie bii bin bip bna bnb bne bni bnn bnp bpa bpb bpe bpi bpn bpp eaa eab eae eai ean eap eba ebb ebe ebi ebn ebp eea eeb eee een eep eia eib eie eii ein eip en- ena enb ene eni enn enp ep- epa epb epe epi epn epp ia- iaa iab iae iai ian iap iba ibb ibe ibi ibn ibp ie- iea iee iei ien iep iia iib iie iii iin iip in- ina inb ine ini inn inp ipa ipb ipe ipi ipn ipp n-i naa nab nae nai nan nap nba nbb nbe nbi nbn nbp ne- nea neb nee nei nen nep nia nib nie nii nin nip nna nnb nne nni nnn nnp npa npb npe npi npn npp p-p paa pab pae pai pan pap pba pbb pbe pbi pbn pbp pea peb pee pei pen pep pia pib pie pii pin pip pn- pna pnb pne pni pnn pnp ppa ppb ppe ppi ppn ppp