restrict qualifier with pointer to a pointer

[Sad Clouds <cryintothebluesky%googlemail.com@localhost>]

I've been looking at various articles, but can't seem to find the right
answer. How do people use C99 restrict qualifier with a pointer to a
pointer data type.

void do_stuff(struct numbers **n);

How do I tell compiler that function parameter 'n' is the only pointer
with which function can access fields inside the structure?

void do_stuff(struct numbers ** restrict n);
or
void do_stuff(struct numbers * restrict *n);
or
void do_stuff(struct numbers * restrict * restrict n);