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_204_812 ( id number, "#" number, "prime minister" text, "date of birth" text, "start date\nof (first) term" text, "age at beginning\nof (first) term" text, "end date\nof (final) term" text, "total time in\noffice" text, "date of death" text, "lifespan" text )

### Question ###
how many prime ministers were born before 1850 ?

### Accurate SQL ###

SELECT COUNT("prime minister") FROM table_204_812 WHERE "date of birth" < 1850