In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[7857, 'I', '7569', 'd', '885', 'N', '8635', 'a', 'a', 't'], ['M', 6487, '7569', 'd', '885', 'N', '8635', 'W', 2199, 2205]