R is a regular local ring of dimension $d$, and $I$ an ideal. If $R/I$ has depth $d − 1$, then $I$ is principal.

Question

is this true?

$R$ is a regular local ring of dimension $d$, and $I$ an ideal. If $R/I$ has depth $d − 1$, then $I$ is principal.

if it is true please help me by a hint

Answer 1

Hint: Try using the Auslander--Buchsbaum formula.