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