In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['Q', 'f', 'I', '9981', 'x', '6665', 'x', 'i', 'd', 'Z', '8259', '9515', 'k', 'p', '3307', '3651', 'v', 5949], [7781, 'S', 'a', 'i', 4869, 2867, 'L', '9981', 'x', '6665', 'x', 'i', 'd', 'Z', '8259', '9515', 'k', 'p', '3307', '3651', 'B', 4309, 'o', 913]