Let G be a finite group and p be a prime. In this paper, we get the sharp bound for |G/O p (G)| p under the assumption that either p 2 ∤ χ(1) for all χ ∈ Irr(G) or p 2 ∤ φ(1) for all φ ∈ IBr p (G). This would settle two conjectures raised by Lewis, Navarro, Tiep,.