a^{v0}_{a0} b^{a1}_{c1} c^{c1,v1}_{c0,a2} eta1^{a2}_{a1} a+(c0) a+(a0) a-(v1) a-(v0)
+a^{v0}_{a1} b^{a2}_{c1} c^{c1,v1}_{c0,a0} gamma1^{a1}_{a2} a+(c0) a+(a0) a-(v1) a-(v0)