Rödl and Tuza proved that sufficiently large -critical graphs cannot be made bipartite by deleting fewer than edges, and that this is sharp. Chen, Erdős, Gyárfás, and Schelp constructed infinitely many -critical graphs obtained from bipartite graphs by adding a matching of size (and called them -graphs). They conjectured that every -vertex -graph has much more than edges, presented -graphs with edges, and suggested that perhaps is the asymptotically best lower bound. We prove that indeed every -graph has at least edges.