b-p bbb bbf bbo bbp bbs bbt bfb bff bfo bfp bfs bft bob bof boo bop bos bot bpb bpf bpo bpp bps bpt bsb bsf bso bsp bss bst btb btf bto btp bts btt fbb fbf fbo fbp fbs fbt fff ffo ffp ffs fft fob fof foo fop fos fot fpb fpo fpp fps fpt fsb fsf fso fsp fss fst ftb ftf fto ftp fts ftt ob- obb obf obo obp obs obt of- ofb off ofo ofp ofs oft oo- oob oof ooo oop oos oot op- opb opf opo opp ops opt os- osb osf oso osp oss ost ot- otb otf oto otp ots ott p-p pbb pbf pbo pbp pbs pbt pfb pff pfo pfp pfs pft pob pof poo pop pos pot ppb ppf ppo ppp pps ppt ps- psb psf pso psp pss pst pt- ptb ptf pto ptp pts ptt sbb sbf sbo sbp sbs sbt sfb sff sfo sfp sfs sft sob sof soo sop sos sot spb spf spo spp sps spt ss- ssb ssf sso ssp sss sst stb stf sto stp sts stt tbb tbf tbo tbp tbs tbt tfb tff tfo tfp tfs tft to- tob tof too top tos tot tpb tpf tpo tpp tps tpt tsb tsf tso tsp tss tst ttb ttf tto ttp tts ttt