CREATE TABLE table_975 ("Quarter" TEXT, "Android" TEXT, "iOS" TEXT, "Symbian" TEXT, "BlackBerry OS" TEXT, "Linux" TEXT, "Windows Phone" TEXT, "Other" TEXT, "Total" TEXT)

How many millions of Blackberry OS smartphones were shipped when 10.4 million Symbian smartphones were shipped?
SELECT "BlackBerry OS" FROM table_975 WHERE "Symbian" = '10.4'
SELECT "BlackBerry OS" FROM "table_975" WHERE "Symbian" = '10.4'