def remove_leading_zeros(num: str) -> str:
    """
    Strips zeros while handling -, M, and empty strings
    """
    if not num:
        return num
    if num.startswith("M"):
        ret = "M" + num[1:].lstrip("0")
    elif num.startswith("-"):
        ret = "-" + num[1:].lstrip("0")
    else:
        ret = num.lstrip("0")
    return "0" if ret in ("", "M", "-") else ret