In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['y', 8539, 'b', 'q', 6843, 5715, '3541', '9885', 'l', '9913', 'f', '7821', '1903', 'W', '1233', '1433', 'C', '4197', '7709', '6741', 'm', 'X', 8409, 4863, 'v', 'H', 'M', 8441, 'H', 4127, 2997, 6647], ['e', 'I', 'z', 'g', 6149, 3271, '3541', '9885', 'l', '9913', 'f', '7821', '1903', 'W', '1233', '1433', 'C', '4197', '7709', '6741', 'H', 2517]