In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['W', 'B', 'y', '7477', '8921', 'M', '5139', '3297', 'R', 'p', 'e', 8139, 7783, 'b', 7533], [8237, 'Y', 'b', 'y', '7477', '8921', 'M', '5139', '3297', 'R', 'p', 'B', 'A', 1525, 8597, 1887, 'Q', 2241, 4473]