In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[5709, 'L', '3149', '9379', 'X', 'J', 'u', 'B', 2381, 1643], ['F', 5781, 8359, 'C', '3149', '9379', 'X', 'J', 'k', 'L', 'M']