In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[9431, 4757, 2171, 'W', '1777', 'l', 'L', 'U', 'k', 'v', 'W', 'm', '2993', 'K', 7935, 'x', 'k', 8965, 9549, 703], ['T', 7513, 'V', 3659, 'H', 'N', '1777', 'l', 'L', 'U', 'k', 'v', 'W', 'm', '2993', 1735, 9177, 'b', 'z', 7317]