ddd ddf ddi dds ddx dfd dff dfi dfs dfx di- did dif dii dis dix dsd dsf dsi dss dsx dxd dxi dxs dxx fdd fdf fdi fds fdx ffd fff ffi ffs ffx fid fif fii fis fix fsd fsf fsi fss fsx fxi fxs fxx i-d i-f idd idf idi ids idx ifd iff ifi ifs ifx iid iif iii iis iix is- isd isf isi iss ixi sdd sdf sdi sds sfd sff sfi sfs sfx sid sif sii sis six ss- ssd ssf ssi sss ssx sxi sxs xdf xdi xds xfs xfx xii xis xix xsi xss xxi xxx