( u v 2 − 2 u v + u + 2 v − 1 ) ( u v 2 − 2 u v − v 2 + 2 v − 1 ) u v 2 {\displaystyle {\frac {\left(uv^{2}-2uv+u+2v-1\right)\left(uv^{2}-2uv-v^{2}+2v-1\right)}{uv^{2}}}}
