drop[6], ooid[5], dior[5], odro[5], ordo[5], poro[5], ropo[5],
dip[5], pod[5], doi[4], ido[4], odo[4], poi[4], odr[4], ord[4], rod[4], por[4], pro[4], rop[4], roi[3], oro[3],
id[3], do[3], od[3], pi[3], op[3], po[3], or[2], ro[2],
