def encode_literal_num(n: int, size: int) -> bytes:
    """Send numbers as literal string in decimal
    `size`: target length of the byte str
    example: 123 -> ["0","0",... , "1","2","3"]
    """
    s = str(n)
    s = "0" * (size - len(s)) + s
    # prevent overflow
    assert s[0] == "0"
    return s.encode("utf-8")