In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[6451, 8721, '7691', '5751', '753', '4885', 'Z', 'T', 3927, 6309], ['Z', 'R', '7691', '5751', '753', '4885', 'Z', 'b', 5507, 719, 3139]