16th All Soviet Union Mathematical Olympiad Problems 1982

1.  The circle C has center O and radius r and contains the points A and B. The circle C' touches the rays OA and OB and has center O' and radius r'. Find the area of the quadrilateral OAO'B. 2.  The sequence an is defined by a1 = 1, a2 = 2, an+2 = an+1 + an. The sequence bn is defined by b1 = 2, b2 = 1, bn+2 = bn+1 + bn. How many integers belong to both