Task: Program Execution
Input (English): 18, 19, ['5091', '7347', '5079', 'K', 'D', 'c', 'S', '8585', '1697', 't', '6371', '1631', '5419', '7091', '6743', 'n', 'h', 'U', 'F', 'A', '973']
Output (English): UF