In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['A', 'f', 's', 619, 'P', '6773', '2907', 'j', 'Y', '3815', '5619', '3681', '1259', 'k', 'k', 'p', '7817', 'e', '1227', 'T', '7201', 'o', 'o', 'W', 'U', 'E', '4881', 'h', '9013', '8427', 'W', 'B', '5309', 'V', 'L'], [7877, 9179, 'B', 'F', 'e', 4663, 'd', 7957, 'F', 'F', 'k', 'f', 8559, 'U', '6773', '2907', 'j', 'Y', '3815', '5619', '3681', '1259', 'k', 'k', 'p', '7817', 'e', '1227', 'T', '7201', 'o', 'o', 'W', 'U', 'E', '4881', 'h', '9013', '8427', 'W', 'B', '5309', 'J', 'R', 't', 'J', 'D', 'U', 'x', 'G', 'y', 'L', 7841, 'g', 's', 8385, 1631, 'Z', 6679, 4419, 'Y', 9253, 3709, 'E', 'a']