-a^{c0,a1}_{c3,a0} b^{c1}_{a2} c^{c3}_{c2} eta1^{a2}_{a1} a+(c2) a+(a0) a-(c1) a-(c0)
+a^{c0,a1}_{c3,a0} b^{c3}_{a2} c^{c2}_{c1} eta1^{a2}_{a1} a+(c1) a+(a0) a-(c2) a-(c0)