In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[9939, 'U', 7753, 'W', 'J', 'I', '9137', 'Y', '6955', '3289', 'z', 'P', '1641', '4951', '1521', 'l', '7333', '8905', 'g', '9239', 'P', '4239', '4015', 'L', 'o', 'X', 'n', 4011, 'k'], [9405, 'e', 'h', 4759, 'w', 4053, 6525, 'x', 'M', 7677, 4391, 'V', 'U', 7157, 'P', 'W', 'J', 'I', '9137', 'Y', '6955', '3289', 'z', 'P', '1641', '4951', '1521', 'l', '7333', '8905', 'g', '9239', 'P', '4239', '4015', 'V', 'Z', 'a', 'u', 715]