In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['C', 391, 1099, 'Q', 'k', 'L', '435', 'e', 'C', 'L', 1199, 'W', 'U', 3897], [8475, 6639, 'Q', 'k', 'L', '435', 'e', 'C', 'b', 'b', 9605, 'O']