def add_to_file(path: str, text: str) -> str:
    with open(path, 'w+') as f:
        for index, char in enumerate(text):

            if f.tell() < 100:
                f.write(char)

            if f.tell() >= 100:
                f.seek(f.tell() - 1, 0)
                f.truncate()

                return text[index:]
    return ''