A point N is marked on the median CM of the triangle ABC so that MN⋅MC=AB2/4. Lines AN and BN intersect the circumcircle △ABC for the second time at points P and Q, respectively. R is the point of segment PQ, nearest to Q, such that ∠NRC=∠BNC. S is the point of the segment PQ closest to P such that ∠NSC=∠ANC. Prove that RN=SN.