In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['i', 'C', 899, 'W', 'v', 'K', 'y', 8087, '4471', 'u', '1535', '6291', '853', '461', 'R', 'Q', 'J', '8859', 'i', 1403], [1273, 'f', 9883, 'i', 'a', 6801, 7191, 7883, '4471', 'u', '1535', '6291', '853', '461', 'R', 'Q', 'J', '8859', 'K', 'H']