unsigned char GetNfactor(unsigned int nTimestamp) {
    int l = 0;
    if (nTimestamp <= StartT)
        return 4;
    unsigned long int s = nTimestamp - StartT;
    while ((s >> 1) > 3) {
      l += 1;
      s >>= 1;
    }
    s &= 3;
    int n = (l * 170 + s * 25 - 2320) / 100;
    if (n < 0) n = 0;
    if (n > 255)
        printf("GetNfactor(%d) - something wrong(n == %d)\n", nTimestamp, n);
    unsigned char N = (unsigned char)n;
      if(N    if(N>maxNfactor) return maxNfactor;
    return N;
}