user: Question: How many different values of total power are there for the unit whose construction started on 01.03.1977 and whose commercial operation started on 01.02.1984?
Columns: ['Unit', 'Type', 'Net power', 'Total power', 'Construction start', 'Construction finish', 'Commercial operation', 'Shut down']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Chinon A1', 'Magnox-Reactor', '70 MW', '80 MW', '01.02.1957', '14.06.1963', '01.02.1964', '16.04.1973']
SQL:

assistant: SELECT COUNT("Total power") FROM "Table" WHERE "Construction start" = '01.03.1977' AND "Commercial operation" = '01.02.1984';