In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[3437, 7225, 'x', '1867', 'u', '8527', 'n', '9693', 'b', '9277', '6881', 'T', '9639', '6405', '2169', '9327', '8725', 't', 'v', 'M', '5049', 'u', 'P', 399, 3189, 't', 'k'], ['d', 5653, 'R', 'B', 5031, 'y', 9953, 7171, 7631, 'l', 'r', 'p', 'X', '1867', 'u', '8527', 'n', '9693', 'b', '9277', '6881', 'T', '9639', '6405', '2169', '9327', '8725', 't', 'v', 'M', '5049', 'p', 6443, 'A', 'H', 'N', 'N', 2255, 'U', 'b', 7955, 'B']