sentences:  Unidirectional errors are errors that only flip ones into zeroes or only zeroes into ones, such as in asymmetric channels.The check bits of Berger codes are computed by counting all the zeroes in the information word, and expressing that number in natural binary.If the information word consists of formula_1 bits, then the Berger code needs formula_2 "check bits", giving a Berger code of length k+n.