− v 3 u 3 + 2 v 2 u 3 − 2 v u 3 + 2 v 3 u 2 − 6 v 2 u 2 + 6 v u 2 + 6 v 2 u − 6 v u + 2 u − 2 v 2 + 2 v − 1 {\displaystyle -v^{3}u^{3}+2v^{2}u^{3}-2vu^{3}+2v^{3}u^{2}-6v^{2}u^{2}+6vu^{2}+6v^{2}u-6vu+2u-2v^{2}+2v-1}
