In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[8421, 'R', 'k', 8603, '7473', 'W', '9531', 'U', 'P', 'k', 'X', 'c', 5305, 'E', 1553, 659], [7009, 'z', 1095, 'i', 'f', '7473', 'W', '9531', 'U', 'P', 'k', 'I', 'C', 6103, 9255, 9267, 9773]