RedirectMatch 301 to change part of URL - .htaccess

Question

There are bad links left over from a previous error, and I'm trying to clean up my mess with 301 RedirectMatch.
Correct URLs are the following format:
http://www.example.com/aaa-directory/page
http://www.example.com/bbb-directory/page
http://www.example.com/ccc-directory/page
(etc.)
But, previously there were bad links that linked to the pages at:
http://www.example.com/aaa-directory//page
http://www.example.com/bbb-directory//page
http://www.example.com/ccc-directory//page
(double backslash // when should be single / )
I've fixed the bad links, but I still get external links and/or robot crawls that go to those bad URLs.
I'd like to use a RedirectMatch 301 so that any link with the text "-directory//" will redirect to the same link with "-directory/".
So, http://www.example.com/ccc-directory//page would be redirected to:
http://www.example.com/ccc-directory/page
I'm struggling with the syntax. Any help would be appreciated!
(not sure if this is needed, but my current HTACCESS file is as follows):
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^(.*)$ $1.html
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]

Answer 1

Keep redirect rules before internal rewrite ones and have another rule to take care of //
RewriteEngine on
RewriteBase /
RewriteCond %{THE_REQUEST} \s/+(.*?)/+(/\S*) [NC]
RewriteRule ^ %1%2 [R=301,L,NE]
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^(.*)$ $1.html [L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php [L]