<IfModule mod_rewrite.c>
  Options +FollowSymlinks
  RewriteEngine On

  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteRule ^(.[a-zA-Z0-9\-\_]+).html$ index.php?mod=$1 [QSA,PT,L]
  RewriteRule ^pay/(.*)$ pay.php?s=$1 [QSA,PT,L]
</IfModule>