In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[8637, 'k', 'x', 8331, 5509, 'x', 'R', '8351', 'g', 'f', '9721', 'J', '7781', 'E', 'C', 2057, 5611, 6001, 'K', 'K'], [7549, 'g', 'z', 'r', 1313, '8351', 'g', 'f', '9721', 'J', '7781', 'E', 'o', 7957, 'n', 'M']