− v 2 u 4 + 3 v u 4 + 4 v 2 u 3 − 9 v u 3 + 4 u 3 − 6 v 2 u 2 + 13 v u 2 − 6 u 2 + 4 v 2 u − 9 v u + 4 u + 3 v − 1 {\displaystyle -v^{2}u^{4}+3vu^{4}+4v^{2}u^{3}-9vu^{3}+4u^{3}-6v^{2}u^{2}+13vu^{2}-6u^{2}+4v^{2}u-9vu+4u+3v-1}
