In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[6797, 2907, 'S', '2567', '431', 'U', '7735', '6089', 'e', 'd', 'y', 'Y', 455, 's', 'J', 6891, 7897], ['T', 9491, 2747, 7439, 'S', '2567', '431', 'U', '7735', '6089', 'e', 'd', 'G', 'x', 'y', 't', 3177]