In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[6971, 5535, 'l', 'o', 'n', '3133', 'e', '5121', 'x', 'M', '1507', '2459', 'X', 'O', 'x', 'U', '4487', '2635', '7963', '4931', '7405', 'E', 'r', 'h', 'w', 'Q', 6115, 'O', 5085, 5127, 7119, 'B', 'B', 'c', 'p', 4019, 'O'], [4205, 's', 'w', 'D', 5979, '3133', 'e', '5121', 'x', 'M', '1507', '2459', 'X', 'O', 'x', 'U', '4487', '2635', '7963', '4931', '7405', 'E', 'r', 'h', 'a', 5179, 'S', 5815, 'y', 7859, 5161, 7317, 3733, 649, 4721]