In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['F', 'X', '7499', '6615', 'x', '5817', '3133', '4321', '5931', '251', 'O', 'J', 'r', 'x', 'i', 'k', 2697, 'u', 'o', 'D', 'z', 'N', 'W', 'J'], [6819, 'W', 'F', 'B', 'E', 'v', 4875, 'Y', 9909, 'o', '7499', '6615', 'x', '5817', '3133', '4321', '5931', '251', 'O', 'J', 'r', 'x', 'A', 253, 6021, 9907, 'f', 'm', 'p', 'J']