− 2 v 3 u 3 + v 2 u 3 + v 3 u 2 − 2 v 2 u 2 − 2 v u + u + v − 2 {\displaystyle -2v^{3}u^{3}+v^{2}u^{3}+v^{3}u^{2}-2v^{2}u^{2}-2vu+u+v-2}
