user: Question: When the launch date is 14.09.2005, and the frequency is 900MHz and 1800MHz, how many carriers are there?
Columns: ['Carrier', 'Standard', 'Frequency', 'Connection speed', 'Launch date (dd.mm.yyyy)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Orange', 'GSM GPRS', '900MHz and 1800MHz', '56 kbit/s', '14.09.2005']
SQL:

assistant: SELECT COUNT("Carrier") FROM "Table" WHERE "Frequency" = '900MHz and 1800MHz' AND "Launch date (dd.mm.yyyy)" = '14.09.2005';