In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[551, 'a', 5641, 9835, 'U', 'f', '6917', 'A', '963', '7599', 'y', 'S', 9727, 8611, 'Y'], ['S', 497, 'f', '6917', 'A', '963', '7599', 'y', 'R', 3469]