Akbar was very pleased with Birbal's game and so offered him a grand reward. "Ask and thou shall receive. I am rich enough to satisfy thy most cherished wish," snapped Akbar. Birbal was hesitant but, on being forced by the emperor, said, "Sir, I will like to have one grain of wheat for the first square on the chessboard, two for second, four for third, and so on for all the 64 squares."     "Is that all?" retorted Akbar. "Birbal, thy request is not worthy of my generosity. Anyhow, thou shall have thy sack of grain."

 What do you think was the size of Birbal' sack?