[sql] subquery in FROM must have an alias

I have this query I have written in PostgreSQL that returns an error saying:

[Err] ERROR:
LINE 3: FROM (SELECT DISTINCT (identifiant) AS made_only_recharge

This is the whole query:

SELECT COUNT (made_only_recharge) AS made_only_recharge
FROM (
    SELECT DISTINCT (identifiant) AS made_only_recharge
    FROM cdr_data
    WHERE CALLEDNUMBER = '0130'
    EXCEPT
    SELECT DISTINCT (identifiant) AS made_only_recharge
    FROM cdr_data
    WHERE CALLEDNUMBER != '0130'
)

I have a similar query in Oracle that works fine. The only change is where I have EXCEPT in Oracle I have replaced it with the MINUS key word. I am new to Postgres and don't know what it is asking for. What's the correct way of handling this?

In the case of nested tables, some DBMS require to use an alias like MySQL and Oracle but others do not have such a strict requirement, but still allow to add them to substitute the result of the inner query.