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