user: Question: What is the U.S. rap rank for the song with a U.S. R&B 23 rank?
Columns: ['Year', 'U.S.', 'U.S. R&B', 'U.S. Rap', 'Album']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1998.0, '—', '106', '—', 'How You Luv That Vol. 2']
SQL:

assistant: SELECT "U.S. Rap" FROM "Table" WHERE "U.S. R&B" = '23';