user: Question: How many had a length of 455?
Columns: ['Number', 'Name', 'Kilometer', 'Pavement', 'Length (m)', 'Average climb (%)']
Types: ['real', 'text', 'real', 'text', 'real', 'real']
Sample row: [17.0, 'Kluisberg', 99.0, 'asphalt', 1250.0, 53.0]
SQL:

assistant: SELECT COUNT("Name") FROM "Table" WHERE "Length (m)" = 455.0;