a-a a-b a-c aaa aab aac aae aap ab- aba abb abc abe abp ac- aca acb acc ace acp aea aeb aec aee aep ap- apa apb apc ape app b-p baa bab bac bae bap bba bbb bbc bbe bbp bca bcb bcc bce bcp be- bea beb bec bee bep bpa bpb bpc bpe bpp c-- caa cab cac cae cap cba cbb cbc cbe cbp cca ccb ccc cce ccp ce- cea ceb cec cee cep cpa cpb cpc cpe cpp eaa eab eac eae eap eba ebb ebc ebe ebp ec- eca ecb ecc ece eea eeb eec eee eep ep- epa epb epc epe epp p-p paa pab pac pae pap pba pbb pbc pbe pbp pca pcb pcc pce pcp pea peb pec pee pep ppa ppb ppc ppe ppp