− v 2 u 4 + v u 4 + 3 v 2 u 3 − 4 v u 3 + 2 u 3 − 4 v 2 u 2 + 7 v u 2 − 4 u 2 + 2 v 2 u − 4 v u + 3 u + v − 1 {\displaystyle -v^{2}u^{4}+vu^{4}+3v^{2}u^{3}-4vu^{3}+2u^{3}-4v^{2}u^{2}+7vu^{2}-4u^{2}+2v^{2}u-4vu+3u+v-1}
