Task: Program Execution
Input (English): 5, ['S', 'x', '1465', '4131', '8593', '63', '1975', 'B', 'K', 'k', '3239', 'J', '3947', '8227', 'B', 'R', 'C', '5481', 'I']
Output (English): S, 63, 3239, R