Here is another suitor and hat problem (much harder than previous one, which was already hard): The three suitors, A, B, and C, are wearing hats with positive integers painted upon them. Each person sees other two numbers, but not his own. Each person knows that the numbers are positive integers (natural numbers) and that one of them is sum of the other two. A, B, then C take turns in the contest to see who can be the first to find out his number. In the first round, A, B, and C all pass, but in the second round, A correctly asserts that his number is 50. Determine the other two numbers, and how did A determine his was 50?