-1/4 a^{v1,v2}_{c3,v0} b^{c3,a0}_{c0,a2} c^{a1,a3}_{c1,c2} gamma1^{a2}_{a3} a+(c0) a+(c1) a+(c2) a+(v0) a-(v2) a-(v1) a-(a1) a-(a0)