In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[5225, 'L', 1023, 8623, 'k', 'f', '1481', 'e', 'm', '4013', 'l', '831', 'n', '3137', 'b', 517], [1243, 't', '1481', 'e', 'm', '4013', 'l', '831', 'n', '3137', 'x', 5545, 's', 'a']