Java, non-static cannot be reference to static context

Doing Java course, at UNI atm, and I'm having a bit of trouble with a dice-problem.

I have the following:

 public class Die {
   public int eyes;
   private java.util.Random r;
   private int n;

   public Die (int n) {
     r = new Random();
     this.n = n;
   }

   public void roll() {
     eyes = r.nextInt(Die.n);
   }

When compiling I get: non-static variable n cannot be referenced from a static context. How would i go about fixing this, whilst having it randomize from a user given value?