Can not rewrite slash rule in htaccess.

I've done a lot of research and this is not a duplicate question. I need to add code in the htaccess to open my page from site.com/page and site.com/page/ to open the same page. There are many codes for this but it won't work for me because I already have a code for it to remove .html ending so far I have this.

    RewriteEngine On
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^([^\.]+)$ $1.html [NC,L]

What can I add to this code to also rewrite if opened with extra slash thanks. God Bless You.