-er a-a a-b a-c aaa aab aac aae aar aav ab- aba abb abc abe abr abv ac- aca acb acc ace acr acv aea aeb aec aee aer aev ar- ara arb arc are arr arv av- ava avb avc ave avr baa bab bac bae bar bav bba bbb bbc bbe bbr bca bcb bcc bce bcr bcv be- bea beb bec bee ber bev bra brb bre brr brv bva bvb bvc bve bvr bvv c-- caa cab cac cae car cav cba cbb cbc cbe cbr cbv cca ccb ccc cce ccr ccv ce- cea ceb cec cee cer cev cra crb crc cre crr crv cva cvb cvc cve cvr cvv eaa eab eac eae ear eav eba ebb ebc ebe ebr ebv ec- eca ecb ecc ece ecr ecv eea eeb eec eee eer eev era erb erc ere err erv eva evb evc eve evr evv ra- raa rab rac rae rar rav rba rbb rbc rbe rbr rca rcb rcc rce rcr rcv re- rea reb rec ree rer rev rra rrb rrc rrr rva rvb rvc rve rvr rvv v-a v-e vaa vab vac vae var vav vba vbc vbr vbv vca vcc vce vcr vea veb vec vee ver vra vrb vrc vre vrr vva vvb vvc vvr vvv