import re import sys def remove_non_digits(line): return re.sub(r'[^0-9\s]', '', line) processed_lines = [] for line in sys.stdin: processed_line = remove_non_digits(line) processed_line = re.sub(r'^\s+|\s+$', '', processed_line) processed_line = re.sub(r'\s+', ' ', processed_line) digit_groups = re.findall(r'\d+', processed_line) if digit_groups: processed_lines.append(' '.join(digit_groups)) print('\n'.join(processed_lines))