zfill filenames that begin with numbers

from pathlib import Path
import os

folder = input('folder relative to this script: ')
ext = input('extension (don\'t include period): ')
target = int(input('# digits: '))

for path in (Path('.') / folder).glob(f'*.{ext}'):
    n, *rest = path.stem.split(' ', 1)
    rest = ''.join(rest)
    n = n.zfill(target)
    name = f'{n} {rest}'.strip() + f'.{ext}'
    os.rename(path, path.parent / name)