In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[5521, 1069, 'O', 'C', '2617', '2939', 'J', 'B', 'H', 'N', 2117, 'x', 'P', 'W', 5259], ['b', 4317, 2659, 'H', 9681, 'C', '2617', '2939', 'J', 'B', 'H', 'J', 7807]