.htaccess remove php extension with pretty url of multiple parameter

I have modified my .htaccess file right now to remove the .php extension to my website. I also have a rule to have a pretty url. My problem however is I'm not sure how to add a second parameter. In addition I wanted to know if it was a problem for the rules if these parameter aren't set.

For example as of now my rules will change mywebsite.com/index.php to mywebsite.com and mywebsite.com/login.php to mywebsite.com/login and mywebsite.com/index.php?week=1 to mywebsite.com/1.

However I have now added a new parameter and my url will now be mywebsite.com/index.php?page=a?week=1 and I would like it to be change to mywebsite.com/a/1 However the "week" or the "page" parameter arent always going to be set. So it could sometimes just be index.php?week=1 or index.php?page=a or they could both be set.

Here are my current rules:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.*)$ $1.php [NC,L]
RewriteRule ^([0-9]+)$ index.php?week=$1
RewriteRule ^([0-9]+)/$ index.php?week=$1

Is what Im asking for even possible?

from .htaccess remove php extension with pretty url of multiple parameter