  A two-coloring of the vertices $V$ of the hypergraph $H=(V, E)$ by red and
blue has discrepancy $d$ if $d$ is the largest difference between the number of
red and blue points in any edge. Let $f(n)$ be the fewest number of edges in an
$n$-uniform hypergraph without a coloring with discrepancy $0$. Erd\H{o}s and
S\'os asked: is $f(n)$ unbounded?
  N. Alon, D. J. Kleitman, C. Pomerance, M. Saks and P. Seymour proved upper
and lower bounds in terms of the smallest non-divisor ($\mbox{snd}$) of $n$. We
refine the upper bound as follows: $$f (n) \leq c \log \mbox{snd}\ {n}.$$
