We accomplish the classification of the reductive symmetric pairs $(G,H)$ for which the dimension of the space $\mathrm{Hom}_{H}(\pi|_{H}, \tau)$ of $H$-intertwining operators is finite for any irreducible smooth representation $\pi$ of $G$ and for any irreducible smooth representation $\tau$ of $H$.

In this note, we prove that if $\{a,b,c,d,e\}$ with $a<b<c<d<e$ is a Diophantine quintuple, then $d<10^{74}$.