z7a−3−2z5a−1 + 5z5a−3−z5a−5 + az3−9z3a−1 + 10z3a−3−3z3a−5 + 4az−14za−1 + 13za−3−3za−5 + 4az−1−11a−1z−1 + 10a−3z−1−3a−5z−1 + az−3−3a−1z−3 + 3a−3z−3−a−5z−3