  This is a short note on the relation between the graded stable derived
categories of 14 exceptional unimodal singularities and the derived category of
K3 surfaces obtained as compactifications of the Milnor fibers. As a corollary,
we obtain a basis of the numerical Grothendieck group similar to the one given
by Ebeling and Ploog (arXiv:0809.2738).
