Nginx if statement rewrite

We have the following if condition with our config,

location ~ ^/$ {
if ($http_user_agent ~* "(iPhone|iPod|iPad|Android|Mobile|Tablet)") {
        rewrite ^ domain.com/mobileversion.php permanent;
       break;
       }

But we also have a subdomain, Now when user enters from mobile phone it affects subdomain also,

How we configure it so if someone enters from mobile phone to subdomain he will not be redirected by the rule above? How can this rule be ignored?