In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[1639, 'j', 9559, 'x', '7759', '6669', 'q', 'S', 'i', '573', 'r', 'u', '7709', '449', 'J', 'N', 'F', 'c', '9035', 'E', 'g', 'L', 6131, 877], ['L', 9089, 3681, 'x', '7759', '6669', 'q', 'S', 'i', '573', 'r', 'u', '7709', '449', 'J', 'N', 'F', 'c', '9035', 'E', 'g', 'n', 9571]