− v 2 u 4 + v u 4 + 5 v 2 u 3 − 5 v u 3 + u 3 − 5 v 2 u 2 + 7 v u 2 − 5 u 2 + v 2 u − 5 v u + 5 u + v − 1 {\displaystyle -v^{2}u^{4}+vu^{4}+5v^{2}u^{3}-5vu^{3}+u^{3}-5v^{2}u^{2}+7vu^{2}-5u^{2}+v^{2}u-5vu+5u+v-1}
