changing the sitecore site’s default url structure

I suggest you specify your language and country so That I can match them in parameters.

Here is a sample for your reference：

<rule name="test" enabled="true" stopProcessing="true">
  <match url=".*" />
   <conditions>
     <add input="{REQUEST_URI}" pattern="^([^/]+)/([^/]+)/(.+)$" />
   </conditions>
  <action type="Redirect" url="http://[www.domain.com]/{C:2}/{C:1}/{C:3}" />
</rule>