a5z−1 + a5z−3−2za3−4a3z−1−3a3z−3 + 2z3a + 4za + 5az−1 + 3az−3−z5a−1−3z3a−1−3za−1−2a−1z−1−a−1z−3 + z3a−3 + za−3