A long time ago, there was1 a king2 in India3. The king's favourite game was chess.

　　One day, a wise4 old man came5 to the place and the king challenged6 him to a game. The king promised7 the old man, "You can have any prize8 if you win the game."

　　The old man said9, "If I win the game, I'd like one grain10 of rice for the first square of the chessboard, two for the second, four for the third, and then double11 the amount12 for each of the rest of the squares."

　　"Is that all?" asked the king. "Wouldn't you like gold or silver14 instead15?"

　　"No, just rice," replied16 the old man.

　　The king and the old man played the game for a long time, Finally17, the old man won18, So the king ordered19 his men to collect a bag of rice. He put one grain on the first square, two on the second, and so on. The king quickly realized20 the problem-even with all the rice in the country, the would13 still not have enough rice to put on all the squares!