-1/2 a^{a0}_{c2} b^{c2}_{a2} c^{a1,a3}_{c0,c1} gamma1^{a2}_{a3} a+(c0) a+(c1) a-(a1) a-(a0)
+1/4 a^{a2}_{c2} b^{c2}_{a3} c^{a0,a1}_{c0,c1} eta1^{a3}_{a2} a+(c0) a+(c1) a-(a1) a-(a0)