In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[1243, 4177, 7243, 'Z', 7721, 5249, 'U', 'U', '4573', 't', 'K', '6303', 'k', 'U', 'r', 3379], ['G', 4413, 'w', 'x', 'p', 'U', 'U', '4573', 't', 'K', '6303', 'k', 'R', 6521, 8315, 'N', 'Y', 'R']