A point $C$ is marked on a chord $AB$ of a circle $\omega.$ Let $D$ be the midpoint of $AC,$ and $O$ be the center of the circle $\omega.$ The circumcircle of the triangle $BOD$ intersects the circle $\omega$ again at point $E$ and the straight line $OC$ again at point $F.$ Prove that the circumcircle of the triangle $CEF$ touches $AB.$