In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[4503, 'f', 'a', '4615', 'y', '2509', 'Z', 'S', 'o', '1657', '5399', 'Q', 8269, 3845, 'v', 2193, 'f', 5421, 'Z'], ['Y', 7899, 7111, '4615', 'y', '2509', 'Z', 'S', 'o', '1657', '5399', 'W', 1951, 't', 2523, 1495]