In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[9889, 1587, 'v', '1781', '7907', 'I', '4089', 'R', 't'], ['C', 1431, 7577, 'B', 'W', 'v', '1781', '7907', 'I', '4089', 'c', 'x', 'Q']