In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[7861, 1423, 'M', 2993, 'H', 'I', 'R', '7489', '9507', 'q', '8921', '3685', '5789', 'W', 'o', 'l', '2961', 'Y', 'j', 2605, 'T', 'u', 'd', 6159, 'T', 1531, 1215], [2531, 'M', '7489', '9507', 'q', '8921', '3685', '5789', 'W', 'o', 'l', '2961', 'f', 'h', 'w', 5283, 7561, 4283, 651, 'G', 'G']