a-a a-c aaa aac aad aae aaf ac- aca acc acd ace acf ad- ada adc add ade adf aea aec aed aee aef af- afa afc afd afe aff c-- caa cac cad cae caf cca ccc ccd cce ccf cda cdc cdd cde cdf ce- cea cec ced cee cef cfa cfc cfd cfe cff daa dac dad dae daf dca dcc dcd dce dcf dda ddc ddd dde ddf de- dea dec ded dee def dfa dfc dfd dfe dff eaa eac ead eae eaf ec- eca ecc ecd ece ecf ed- eda edc edd ede edf eea eec eed eee eef ef- efa efc efd efe eff faa fac fad fae faf fca fcc fcd fce fcf fda fdc fdd fde fdf fea fec fed fee fef ffa ffc ffd ffe fff