You will be given a definition of a task first, then some input of the task.
In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.

[2321, 2913, 2557, 'S', 1571, 'r', 'g', 'W', '4649', 'B', 'S', '1019', 'j', 'g', 'x', 'T', 'k', 'F', 'p', 'W', 'L', 7711, 2017, 7247, 839], ['x', 'y', 'w', 'F', 7947, 8291, 'q', 'r', 'g', 'W', '4649', 'B', 'S', '1019', 'j', 'g', 'x', 'T', 'k', 'F', 'p', 'W', 'C', 'Z', 'f']
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
r, g, W, 4649, B, S, 1019, j, g, x, T, k, F, p, W