I want to increase my Sitecore session timeout for CMS.

I have changed the below three changes but still it is not working.
<setting name="Authentication.ClientSessionTimeout" value="180" />

<authentication mode="None">
  <forms name=".ASPXAUTH" cookieless="UseCookies" timeout="180" />
</authentication>

<sessionState mode="InProc" stateConnectionString="tcpip=127.0.0.1:42424" sqlConnectionString="data source=127.0.0.1;user id=sa;password=" cookieless="false" timeout="180" />


Can anyone please help or have any idea on this?