In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['X', 9619, 'r', 'R', 'L', 'E', '2631', 'N', '615', 'x', '3851', 'z', 'Y', 1601, 43], ['M', 7325, 4167, 'L', 'E', '2631', 'N', '615', 'x', '3851', 'z', 'R', 'l', 2123]