user: Question: How many region 1's did Back to Earth have?
Columns: ['Release', '# of discs', 'Region 1', 'Region 2', 'Region 4']
Types: ['text', 'real', 'text', 'text', 'text']
Sample row: ['Series I', 2.0, '25 February 2003', '4 November 2002', '3 December 2002']
SQL:

assistant: SELECT COUNT("Region 1") FROM "Table" WHERE "Release" = 'Back to Earth';