Hide .html extension for only public_html files

Question

I make the .htaccess to hide all .html extension for all files hosted in the public_html but I don't want it to affect the rest of the directories since there are .php files.

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/$ $1.html
RewriteRule ^([^/]+)/([^/]+)/$ /$1/$2.html
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(\.[a-zA-Z0-9]{1,5}|/)$
RewriteRule (.*)$ /$1/ [R=301,L]