import pyperclip
import time
import re
while True:
        s = pyperclip.paste()
        x = re.match("(\d{3})(\d{3})(\d{3})", s)
        if x:
                pyperclip.copy("+420 {} {} {}".format(x.group(1), x.group(2), x.group(3)))
        time.sleep(0.2)