In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[3237, 503, 'U', 5757, 9759, 'k', 6489, 'x', 'x', 'M', 'u', 'I', '2501', '5555', 'k', 'P', 'A', 'p', 'q', '7141', 's', 'z', 'c', 'v', 171, 'x', 4717, 'q', 7813, 5201, 'S', 2821, 'h', 6421, 9639], ['h', 899, 5891, 2235, 195, 'D', 'L', 'u', 'I', '2501', '5555', 'k', 'P', 'A', 'p', 'q', '7141', 's', 'z', 'c', 'P', 3579]