In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[1853, 9719, 'U', 'U', 'D', 2565, 'I', 2887, 2923, 'U', 'F', 'Y', '837', 'x', '9209', '9735', 'M', 'P', '4105', 'q', 'b', 'y', 'S', '2827', 'G', '8197', 'm', 'o', 5205, 1551, 'K', 3851, 9759, 'r'], [4163, 477, 2339, 1523, 421, 71, 3159, 2487, 'G', 'P', 'Y', '837', 'x', '9209', '9735', 'M', 'P', '4105', 'q', 'b', 'y', 'S', '2827', 'G', '8197', 'm', 'k', 9645, 303, 'x', 4347, 8621, 'T', 9567, 'l', 7097, 'N']