In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[7639, 9217, 'f', 'u', 'D', 'o', 't', 7117, 'A', 8039, 'j', 'T', 'q', '2491', '9177', 'L', '3665', 'w', 'c', 'y', '5131', '4517', 'n', 'i', '7517', '545', 'b', 'T', 'w', 'n'], [269, 8457, 2129, 757, 'x', 'l', 'Y', '2491', '9177', 'L', '3665', 'w', 'c', 'y', '5131', '4517', 'n', 'i', '7517', '545', 'J', 'M', 7861]