In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[5415, 4787, 'W', 'H', '9221', '8093', '9839', 'f', 'g', '6929', 'B', '1859', 'g', 5507, 'u', 'z', 6787, 387, 9409], ['v', 'W', 8563, 2125, 'W', 'H', '9221', '8093', '9839', 'f', 'g', '6929', 'B', '1859', 'I', 'H', 5587, 'n', 'w', 4493, 'M']