hi all!!

i m preparing for post-graduation..........just checking prev years' papers n found this interesting ques!! but can't figure out the answer.....plz help me!!

Let A be a sequence of 8 distinct integers sorted in ascending order. How many distinct pairs of sequences, Band C are there such that (i) each is sorted in ascending order, (ii) B has 5 and C has 8 elements, and (iii) the result of merging B and C, gives A ?

thnx!!