In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['K', 'x', 8473, 4921, 'M', 'B', 'i', '9333', 'K', '3571', 'o', '301', 'L', 'B', 'b', 851], ['f', 'R', 3077, 'M', 'P', 'i', '9333', 'K', '3571', 'o', '301', 'L', 'B', 'O', 1217]