\frac{\delta _{r}X}{\delta {\mkern0mu\underline{\mkern-0mu\smash{\Phi }\mkern-0mu}\mkern0mu }^{\alpha }}\frac{\delta _{l}Y}{\delta {\mkern0mu\underline{\mkern-0mu\smash{K}\mkern-0mu}\mkern0mu }_{\alpha }}-\frac{\delta _{r}X}{\delta K_{\alpha }}\frac{\delta _{l}Y}{\delta \Phi ^{\alpha }}