ddd ddf ddi dds ddt ddx dfd dff dfi dfs dft dfx di- did dif dii dis dit dix dsd dsf dsi dss dst dsx dtd dtf dti dts dtt dtx dxd dxi dxs dxt dxx fdd fdf fdi fds fdt fdx ffd fff ffi ffs fft ffx fid fif fii fis fit fix fsd fsf fsi fss fst fsx ftd ftf fti fts ftt ftx fxi fxs fxt fxx i-d i-f idd idf idi ids idt idx ifd iff ifi ifs ift ifx iid iif iii iis iit iix is- isd isf isi iss ist itd itf iti its itt itx ixi sdd sdf sdi sds sdt sfd sff sfi sfs sft sfx sid sif sii sis sit six ss- ssd ssf ssi sss sst ssx std stf sti sts stt stx sxi sxs sxt t-x tdd tdf tdi tds tdt tdx tfd tff tfi tfs tft tfx tid tif tii tis tit tix tsd tsf tsi tss tst tsx ttd ttf tti tts ttt ttx txf txi txs txt xdf xdi xds xdt xfs xft xfx xii xis xit xix xsi xss xst xtf xti xts xtx xxi xxx