class Solution:
def licenseKeyFormatting(self, s: str, k: int) -> str:
while "-" in s:
s = s.replace("-", "")
s = s.upper()
fk = ""
while True:
if len(s) <= k:
fk = s + fk
break
fk = "-" + s[-k:] + fk
s = s[:-k]
return fk