while True: try: # 1. 读取整行 s = input() # 2. 记录非字母字符的位置 non_alpha = [(i, c) for i, c in enumerate(s) if not c.isalpha()] # 3. 提取并排序字母 letters = [c for c in s if c.isalpha()] sorted_letters = sorted(letters, key=lambda x: x.lower()) ...