In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['f', 2397, 7269, 9923, 31, 'E', 'I', 'p', 'Y', 'v', 401, 'B', 9637, 'x', 'x', 'm', 7057, 'C', 7939, 'y', 'b', 'b', 7435, 'U', 'R', '2175', 'r', '4215', 'P', 'j', 'w', 'T', 'v', 'k', '9721', 'r', 'f', '639', '973', 'f', '6247', 'F', 'u', 'a', 'a', 'O', '6507', 'g', 8457, 7991, 675], ['N', 'b', 8381, 957, 3307, 179, 4807, 'H', 439, 4171, 6487, 4439, 'V', 'g', 'E', 'W', 'g', 'Q', 8649, 6117, 5409, 'E', 'U', 'R', '2175', 'r', '4215', 'P', 'j', 'w', 'T', 'v', 'k', '9721', 'r', 'f', '639', '973', 'f', '6247', 'F', 'u', 'a', 'a', 'O', '6507', 'X', 3309, 'v', 'p', 'v', 'O', 4281, 4359, 6713, 'I', 4435, 8573, 'x', 'N', 'x']