In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[429, 'W', 6609, 3011, 8879, 'L', 8071, '6913', '31', 'D', '8045', '4777', 'i', 'Q', '1493', 'H', 1929], [2983, 7999, '6913', '31', 'D', '8045', '4777', 'i', 'Q', '1493', 'l', 'B', 'C', 1215, 'X', 1911, 'H', 'X']