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