How do I correct my .htaccess code?

Hello, I presently have the following in the .htaccess code in my root folder:

RewriteCond %{REMOTE_HOST} !^
RewriteCond %{REQUEST_URI} !^/american-university-rome/?
RewriteCond %{REQUEST_URI} /(.*)$
RewriteRule (.*) /american-university-rome [R=301,L]

It works fine, EXCEPT, I need the redirect limited to the root folder only, i.e., "," and not to any other sub-directory.

In other words, if someone puts in "," then it needs to go to "," BUT, if someone puts in "" (as an example) then it needs to stay there and NOT be redirected to ""

Can you help?