def autoname(ind):
    """Automatically turn an index into a system name."""
    # sequence A-Z, AA-AZ-ZZ, AAA-AAZ-AZZ-ZZZ ...
    chars = []
    while True:
        chars.append(chr(65 + ind % 26))
        if ind < 26:
            break
        ind = ind // 26 - 1
    return "System " + "".join(chars[::-1])