Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_19246_1 (carrier VARCHAR, frequency VARCHAR, launch_date__ddmmyyyy_ VARCHAR)
### Question:
When the launch date is 14.09.2005, and the frequency is 900mhz and 1800mhz, how many carriers are there?
### Answer:
SELECT COUNT(carrier) FROM table_19246_1 WHERE frequency = "900MHz and 1800MHz" AND launch_date__ddmmyyyy_ = "14.09.2005"