birr[6], bris[6], biss[6], sirr[4], riss[4], sirs[4], surr[4], russ[4],
brr[5], bis[5], bus[5], irr[3], sir[3], iss[3], rus[3], sur[3], urs[3],
bi[4], si[2], ui[2], ur[2],
