-1/2 a^{a2}_{a0} b^{c0,c1}_{c4,a1} c^{c3,c4}_{c2,a3} eta1^{a3}_{a2} a+(c2) a+(a0) a+(a1) a-(c3) a-(c1) a-(c0)
+1/2 a^{a2}_{a0} b^{c0,c1}_{c4,a3} c^{c3,c4}_{c2,a1} eta1^{a3}_{a2} a+(c2) a+(a0) a+(a1) a-(c3) a-(c1) a-(c0)