def rot13(word):
return ''.join(chr(ord(c) + (13 if c.lower() < 'n' else -13)) for c in word)
print(rot13('hello'))
print(rot13(rot13('hello')))
ZGVmIHJvdDEzKHdvcmQpOgoJcmV0dXJuICcnLmpvaW4oY2hyKG9yZChjKSArICgxMyBpZiBjLmxvd2VyKCkgPCAnbicgZWxzZSAtMTMpKSBmb3IgYyBpbiB3b3JkKQoJCnByaW50KHJvdDEzKCdoZWxsbycpKQpwcmludChyb3QxMyhyb3QxMygnaGVsbG8nKSkp