19. The amount 4.5 is split into two nonnegative real numbers uniformly at random. Then each number is rounded to its nearest integer. For instance, if 4.5 is split into $\sqrt{2}$ and $4.5-\sqrt{2}$, then the resulting integers are 1 and 3 , respectively. What is the probability that the two integers sum up to 5 ?
19. $4 / 9$