Favourite String of Chef

A string $S$ is called *Chef's favourite* if every substring `chef` in $S$ must have a substring `code` before it. You are given a string $S$ of size $N$ that contains both `code` and `chef` as a substring. Please determine if $S$ is Chef's favourite. **Note**: A substring is a continuous part of string which can be obtained by deleting some (may be none) character's from the beginning and some