Task: Program Execution
Input (English): 1, 6, ['2151', 'e', 'W', 'L', '517', '1239', '7457', 'y', '8513', '993', '3965', '2947', '2753', '7187', 'M', 'a', '9223', '3809', '7311', '793', 'M', 'u', 'I', 'p', 'a', '7881']
Output (English): 2151, 7457, 2753, 7311, a