I messed up the function.php on my site

I messed up the function.php on my site.

I was trying to remove the login bar at the top of the homepage and added:

add_filter(‘show_admin_bar’, ‘__return_false’)

to the end of the script. Now I can’t access the backend at all!

When I log in I just get the text:

add_filter(‘show_admin_bar’, ‘__return_false’);

How can I go back into the backend to remove this?