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