Parallelograms

In the quadrilateral $PQRS$ , $A$ , $B$ , $C$ and $D$ are the midpoints of the sides $PQ,QR,RS$ and $SP$ respectively, and $M$ is the midpoint of $CD$ . Suppose $H$ is the point on the line $AM$ such that $HC=BC$ . Find $\angle BHM$ in degrees.