Let ABCABC be an acute-angled triangle such that AB<ACAB < AC. Let DD be the point of intersection of the perpendicular bisector of the side BCBC with the side ACAC. Let PP be a point on the shorter arc ACAC of the circumcircle of the triangle ABCABC such that DPBCDP \parallel BC. Finally, let MM be the midpoint of the side ABAB. Prove that APD=MPB\angle APD = \angle MPB.