In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['P', 5281, 'x', 997, 'x', 'E', 2253, 'I', 'D', 'd', 'P', 'i', 'h', '6681', '3909', 'h', 'D', 4209], [5665, 'U', 'I', 'D', 'd', 'P', 'i', 'h', '6681', '3909', 'h', 'd', 'e', 461, 2005, 'f', 'I', 5843]