In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[7515, 4253, '3149', '1971', 'D', '4235', 'A', 'n', 7357, 1339, 959, 'r'], [9017, 377, 'J', 591, '3149', '1971', 'D', '4235', 'A', 'f', 'u']