In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['N', 8205, 'J', 2351, 6985, 'h', '5473', '6307', '6821', 'S', 'I', 5315], ['U', 'S', 2077, 2823, 'y', 'h', '5473', '6307', '6821', 'S', 'a', 'a', 8685, 's', 'u']