In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
[861, 6555, 6891, 719, 'a', 'k', 'a', 'u', '1071', '7453', '4217', 's', '2423', 'G', '709', '4565', '4731', '4969', 'u', 'K', '2173', '1537', 'D', '5943', '1539', 'm', 5031, 1095], ['R', 7379, 5877, 5743, 'i', 8499, '1071', '7453', '4217', 's', '2423', 'G', '709', '4565', '4731', '4969', 'u', 'K', '2173', '1537', 'D', '5943', '1539', 'R', 3699, 'R', 'G']