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_name_51 (grid VARCHAR, laps VARCHAR, driver VARCHAR)

### Question ###
When driver heinz-harald frentzen has a number of laps greater than 60, what is the sum of grid?

### Accurate SQL ###

SELECT COUNT(grid) FROM table_name_51 WHERE laps > 60 AND driver = "heinz-harald frentzen"