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