Task: Program Execution
Input (English): 1, 7, ['z', '9643', 'J', 'z', '4173', '2669', '5657', 'W', '7551', 'v', '8503', '407', '1141', '3571', 'S', '9801', '1075', 'U', 'E', '2777', 'y', '6555', '4049', '9157']
Output (English): z, W, S, 6555