Task: Program Execution
Input (English): 5, 12, ['6945', '4669', '9721', 'X', '543', '3355', '8517', 'a', '4983', '7007', '7379', '3249', 'l', '8859', 'Q', '1453', 'C', 'u', '9147', '4665', '1349', 'R', 'Q', 'I', '6129']
Output (English): 543, C