Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_18 (founded INTEGER, stadium VARCHAR, club VARCHAR)

### Question ###
What year was the team Club of atlético de san juan fc who plays at hiram bithorn stadium founded.

### Accurate SQL ###

SELECT SUM(founded) FROM table_name_18 WHERE stadium = "hiram bithorn stadium" AND club = "atlético de san juan fc"