In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['W', 'Y', 'y', 'A', 'm', '6915', '3285', 'd', '1035', 'H', 'J', '7549', 'P', '5301', 'q', '4057', 'H', '5697', 'H', '5141', 'H', 2451, 'x', 3307, 'A', 7121, 'b', 3319], ['M', 'L', 5827, 'I', 'r', 'f', '6915', '3285', 'd', '1035', 'H', 'J', '7549', 'P', '5301', 'q', '4057', 'H', '5697', 'H', '5141', 'N', 3371, 691]