Task: Program Execution
Input (English): 5, 6, ['b', '8447', '1949', '7847', 'X', '3935', 'I', '8715', 'S', '3517', '3043', '6341', '6487', 'x', 'O', '1299', '1457', 'E', '9275', 'z']
Output (English): X3935