− v 3 u 3 + 3 v 2 u 3 − 2 v u 3 + v 3 u 2 − 4 v 2 u 2 + 2 v u 2 + 2 v 2 u − 4 v u + u − 2 v 2 + 3 v − 1 {\displaystyle -v^{3}u^{3}+3v^{2}u^{3}-2vu^{3}+v^{3}u^{2}-4v^{2}u^{2}+2vu^{2}+2v^{2}u-4vu+u-2v^{2}+3v-1}
