user: Question: What is the coinage metal for KM numbers of S45?
Columns: ['Location', 'Date', 'Denomination', 'Coinage metal', 'Mintage', 'KM number']
Types: ['text', 'real', 'text', 'text', 'real', 'text']
Sample row: ['Fribourg', 1934.0, '00005 5 francs', 'Silver', 40650.0, 'S18']
SQL:

assistant: SELECT "Coinage metal" FROM "Table" WHERE "KM number" = 'S45';