that because the width here s s is really probability of the civil sequence so that's achieving entropy coding up to the rounding out the problem here is done these codes are not a set of prefix codes for example we have one here that we would send for a second symbol but after we receive one we wouldn't know did they send us a second symbol or was it the third symbol so the second symbol sent twice or the third symbol sent once there's no disambiguation and so this scheme while we might seem reasonable at first and it's efficient it actually