In this task, you are given two lists A,B. Find the longest common subsequence in the lists A and B.
['U', 6099, 6083, 'W', 'f', 'I', '2923', 'I', 'v', 'k', 2221], ['T', 6595, 9211, 'f', 'I', '2923', 'I', 'm', 145, 4053]