bier[6], brei[6], brie[6], reib[6], rieb[6], birr[6], bure[6], irre[4],
bei[5], erb[5], brr[5], ire[3], irr[3], reu[3], ure[3],
bi[4], ei[2], er[2], re[2], ui[2], ur[2],
