a-a a-b a-c aaa aab aac aad aae aaf ab- aba abb abc abd abe abf ac- aca acb acc acd ace acf ad- ada adb adc add ade adf aea aeb aec aed aee aef af- afa afb afc afd afe aff baa bab bac bad bae baf bba bbb bbc bbd bbe bbf bca bcb bcc bcd bce bcf bda bdb bdc bdd bde bdf be- bea beb bec bed bee bef bfa bfb bfc bfd bfe bff c-- caa cab cac cad cae caf cba cbb cbc cbd cbe cbf cca ccb ccc ccd cce ccf cda cdb cdc cdd cde cdf ce- cea ceb cec ced cee cef cfa cfb cfc cfd cfe cff daa dab dac dad dae daf dba dbb dbc dbd dbe dbf dca dcb dcc dcd dce dcf dda ddb ddc ddd dde ddf de- dea deb dec ded dee def dfa dfb dfc dfd dfe dff eaa eab eac ead eae eaf eba ebb ebc ebd ebe ebf ec- eca ecb ecc ecd ece ecf ed- eda edb edc edd ede edf eea eeb eec eed eee eef ef- efa efb efc efd efe eff faa fab fac fad fae faf fba fbb fbc fbd fbe fbf fca fcb fcc fcd fce fcf fda fdb fdc fdd fde fdf fea feb fec fed fee fef ffa ffc ffd ffe fff