There are 4 mathematicians - Clark, Lee, Martin and Harris - having lunch in a hotel. Suddenly, Clark thinks of 2 integer numbers greater than 1 and says, "The sum of the numbers is..." and he whispers the sum to Lee. Then he says, "The product of the numbers is..." and he whispers the product to Martin. After that following conversation Lee told Martin, I don't think that we know the numbers. Martin : Aha!, now I know the numbers. Lee : Oh, now I also know the numbers. Harris : Now, I also know the numbers. What are the numbers? Explain your answer ?