how to redirect everything from https to http except WP admin?

After a migration we have the below in the WP htaccess to redirect everything from https to http:

RewriteCond %{SERVER_PORT} 443
RewriteRule ^(.*)$ http://examplesite.com/blog/$1 [R=301,L]

But we want to have the wordpress admin on SSL.

What exception should be added to the above rule and how?

Would this be the right way to do it?

Update:
How can I exclude /wp-admin/ and wp-login.php from the above condition? (please, note the blog is in the subfolder /blog and the htaccess is there too)