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_203_653 ( id number, "rank" number, "nation" text, "gold" number, "silver" number, "bronze" number, "total" number )

### Question ###
how many more silver medals did the united states win compared to russia ?

### Accurate SQL ###

SELECT (SELECT "silver" FROM table_203_653 WHERE "nation" = 'united states') - (SELECT "silver" FROM table_203_653 WHERE "nation" = 'russia')