ddd ddi ddo ddp dds di- did dii dio dip dis dod doi doo dop dos dpd dpi dpo dpp dps dsd dsi dso dsp dss i-d idd idi ido idp ids iid iii iio iip iis io- iod ioi ioo iop ios ipd ipi ipo ipp ips is- isd isi iso isp iss o-i odd odi odo odp ods oid oii oio oip ois oo- ood ooi ooo oop oos op- opd opi opo opp ops os- osd osi oso osp oss p-p pdd pdi pdo pdp pds pid pii pio pip pis pod poi poo pop pos ppd ppi ppo ppp pps ps- psd psi pso psp pss sdd sdi sdo sdp sds sid sii sio sip sis sod soi soo sop sos spd spi spo spp sps ss- ssd ssi sso ssp sss