Joomla - How to get rid of "/index.php/ru/" only on the main page?

Question

Joomla

The site is migrating 1.7 -> 3.4.5
The materials have been moved. There are redirects left.
FAQ read - did not help. All hope is in you.
Now all urls contain "/inex.php/ru/"
Task: Only! remove "/index.php/ru/" from the main page (i.e. get http://site.com)
All other URLs must contain "/index.php/ru/" (i.e. site.com/ index.php/en/contact)
- SEF enabled
- URL redirection disabled
- Languages: Rus, Eng. (The site is not multilingual. The language was added for the necessary formation of /ru/)
- .htaccess content (tried to add rules - did not work / cyclic redirect)