Inactivity Timeout in silverlight application

I have a Navigation Fra开发者_Python百科me in my MainPage.xaml whose content is set to Login.xaml. From the LoginPage.xaml, I navigate to other pages as follows:

this.NavigationService.Navigate(new Uri("/SecondPage.xaml", UriKind.Relative));

I need to implement a timoout on user inactivity that redirects to the Login.xaml from any page after 1 minute of inactivity (keyboard & mouse).

How can I do this.

EDIT: I need to call some clean up routines also when timeout happens.