def min_letter_index(string: str) -> int:
    """
    :param string: str to work with.
    :return: min index of letter symbol in the string;
     -1 if the string is empty, 2000 if there's no letter symbol.
    """
    if not string:
        return -1

    return min(
        ord(symbol.lower()) if symbol.isalpha() else 2_000
        for symbol in string
    )