Your code indicates that the using statement is
At first glance, this is not a .net library namespace so the only person who can tell you what namespace to use is whoever wrote that library.
A quick google search may lead me to believe you made a mistake and mean to use System.Windows.Input?
If you didn't mean System.Windows.Input then I am afraid you need to talk with other people working on your project or the person who wrote your library. Remember, we don't have access to your hard rive, we don't have access to your code nor do we read minds or know anything about your project.
This issue is pretty clear however, you either have a type in your namespace or are using the wrong namespace of a library your team/members of your project have decided to use.