Resolved Deleting products that are not in csv file

Hi,
I am importing products to Virtuemart from remote csv file. In that file some of products are deleted and those product should be deleted from website too.
Example;
in CSV file there are products: a, b, c, d, e, after import those are in webste too.
After in CSV file there are products: b,c, d, e, how to delete product "a" on a website, actually how to synchronize ?

Thank you,
Milos