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