Task: Program Execution
Input (English): 21, 21, ['4621', 'a', '1087', '575', 'E', 'M', 'j', 'H', '1853', '8499', 'e', '899', '9583', '3945', 'S', 'x', 'V', '1433', '5711', 'b', 'x', '6657', '899', '8701']
Output (English): x