  For each integer k > 1, Johnson gave a 3-manifold with Heegaard splittings of
genera 2k and 2k-1 such that any common stabilization of these two surfaces has
genus at least 3k-1. We modify his argument to produce a 3-manifold with two
Heegaard splitings of genus 2k such that any common stabilization of them has
genus at least 3k.
