In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[6731, 'U', 3385, 'a', 'Q', '2103', '1781', '2215', 'I', 4463, 'N'], [3807, 1105, 'F', 'r', 'a', 'Q', '2103', '1781', '2215', 'y', 7587]