The quadrilateral ABCD is inscribed in the circle ω. Lines AD and BC intersect at point E. Points M and N are selected on segments AD and BC, respectively, so that AM:MD=BN:NC. The circumscribed circle of the triangle EMN intersects the circle ω at points X and Y. Prove that the lines AB,CD and XY intersect at the same point or are parallel. geometryKharkivcirclesconcurrencycircumcircleCyclic