.htaccess RewriteRule then 1 then 2 variables how to solve?

Question

htaccess

When there are two variables, for example site.ru/moskva/one-page,
then everything is fine, but when there is only 1 variable, for example, "moskva" - then troubles.

RewriteRule ^([0-9a-z\.\-]+)/([0-9a-z\.\-]+)/?$ index.php?city=$1&page=$2 [L]

tell me good people!