user: Question: How many ERP W is it that has a Call sign of W273BS?
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'Height m ( ft )', 'FCC info']
Types: ['text', 'real', 'text', 'real', 'text', 'text']
Sample row: ['W261BG', 100.1, 'Morrow, Georgia', 5.0, 'm (ft)', 'FCC']
SQL:

assistant: SELECT "ERP W" FROM "Table" WHERE "Call sign" = 'W273BS';