In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['R', 'Q', 'Q', 'e', 'C', 'U', 'T', '7509', '8471', 'S', 407, 793], ['G', 'D', 'C', 'U', 'T', '7509', '8471', 'l', 'r', 7861, 6959, 1617]