Einstein number of Joris Van der Jeugt

Most mathematicians are familiar with the definition of one's Erdös number, see the Erdös Number Project Web site.
I have heard physicists talk about their Einstein number: Einstein's own Einstein number is 0. His co-authors have Einstein number 1. People other than Einstein who have written a joint paper with someone with Einstein number 1 but not with Einstein himself have Einstein number 2, and so on.
I think that my own Einstein number is currently 4; one possible path is:
   Robert T. SHARP
      Marcos MOSHINSKY
         V. BARGMANN
            A. EINSTEIN

Joris Van der Jeugt 28 May 1997