def METHOD_NAME(self, count):
    comb_all = self._comb(self.num, self.num_half)
    comb_le_count = 0
    for i in range(count + 1):
        tmp = self._comb(self.num_half, i)
        comb_i = tmp * tmp
        comb_le_count += comb_i
    prob = comb_le_count / comb_all
    return prob