In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['H', 'E', 'X', 'p', '7949', '2285', 'w', 'R', '4939', 'e', 'x', 'O', 'W', 1391, 'U', 4939, 6899, 5849, 'W', 5293], ['w', 'T', 'x', 8691, 'S', 'W', 'O', 2131, 'X', 'p', '7949', '2285', 'w', 'R', '4939', 'e', 'x', 'B', 'x', 4449, 'Q', 3531, 'Y', 'B', 'F']