In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['r', 1357, 'K', 'Y', 'G', 'o', '9699', '4635', 'E', 'U', 'M', 'S', 'S'], [4589, 4217, 8377, 'G', 'o', '9699', '4635', 'E', 'U', 'a', 't', 6989, 7039, 'Y', 'K']