$S$ is a sufficient condition for $P$, and $R$ is a necessary condition for $P$.
So, whenever $S$ is true, then $P$ is true. And whenever $P$ is true then $R$ is true. So, whenever $S$ is true, then $R$ is true(because when $S$ becomes true, then $P$ becomes true, then $R$ becomes true because $P$ has become true).
So, $S$ implies $R$. So, $S$ is a sufficient condition for $R$.
So, Whenever $S$ is true, $R$ is True.
So, sufficient condition for $P$ implies necessary condition for $P$.