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_17257687_1 ( episode_number VARCHAR, event_4 VARCHAR, event_1 VARCHAR )

### Question ###
On which episode number is event 4 The Wall and event 1 the Pendulum?

### Accurate SQL ###

SELECT COUNT(episode_number) FROM table_17257687_1 WHERE event_4 = "The Wall" AND event_1 = "Pendulum"