In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['n', 'C', 6023, 'L', 'M', '6979', 'r', '1707', 'd', 'g', 'L'], [9703, 'Y', 'V', 'M', '6979', 'r', '1707', 'i', 3877, 4381, 'd']