Points C0 and B0 are the respective midpoints of sides AB and AC of a non-isosceles acute triangle ABC, O is its circumscenter and H is the orthocenter. Lines BH and OC0 intersect at P, while lines CH and OB0 intersect at Q. OPHQ is rhombus. Prove that points A, P and Q are collinear. (Author: L. Emelyanov) geometryrhombuscircumcircleangle bisectorgeometry proposed