In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[2345, 'S', 'x', '8439', 't', '2633', 'W', '3151', 'J', 'a', 1235], [7869, 1407, 'V', 'C', '8439', 't', '2633', 'W', '3151', 'J', 'g', 'I', 6769, 9099, 3465, 'l']