:type s: str
    :rtype: int

def first_unique_char(s):
    """
    :type s: str
    :rtype: int
    """
    if (len(s) == 1):
        return 0
    ban = []
    for i in range(len(s)):
        if all(s[i] != s[k] for k in range(i + 1, len(s))) == True and s[i] not in ban:
            return i
        else:
            ban.append(s[i])
    return -1