In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['A', 'A', 'C', 'E', 'N', 'K', '4287', 'J', '3375', '7765', 'y', 'U', 'H', 'b', 'I', 'L', 'S', 'u', 7491], [9547, 277, 'j', 'K', '4287', 'J', '3375', '7765', 'y', 'U', 'H', 'b', 'I', 'L', 'S', 'L', 3541]