web config - Using RegExp in IIS rewrite statements -

i have set of pages need rewrite handler using iis's web.config file. final structure should this:

mydomain.com/es/mexico

this needs mapped to:

international.php?lang=es&country=mexico

the language code, however, won't there - if types in "mydomain.com/mexico" should redirected to:

international.php?country=mexico

i tried set in web.config, whenever try add second querystring hit web.config server error. can help?

try like:

^(?:/([a-za-z0-9]{2})?)?(?:/(.{3,}))

language (2 letters) matched {r:1}

country (3+ letters) matched {r:2}

TY