In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[6071, 'q', 9821, 'l', 'g', 'B', 'R', 'x', 6477, '5489', 'Y', 'f', 'R', '7209', '1673', '8797', '4547', '2763', '3709', 'A', '751', 'B', 'c', 7177, 'x', 'd', 665, 3253, 'Z', 'f', 4665], [1321, 5823, 8703, '5489', 'Y', 'f', 'R', '7209', '1673', '8797', '4547', '2763', '3709', 'A', '751', 'a', 2763]