Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: 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?

### Accurate SQL ###

SELECT COUNT(carrier) FROM table_19246_1 WHERE frequency = "900MHz and 1800MHz" AND launch_date__ddmmyyyy_ = "14.09.2005"