In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['p', 'Q', 'C', 'j', '9919', 'o', 'u', '3401', 'e', 'S'], [9921, 2261, 8515, 1545, '9919', 'o', 'u', '3401', 'm', 6101, 'T', 2491]