During the year ended on 30 June 2020, a subsidiary entity sold inventories to its parent entity for $18 000. The inventory had originally cost the subsidiary $4 000. The parent entity sold 30% of the inventory transferred from the subsidiary to an external party during the year. The company tax rate is 30%.

Required:

What is the amount of adjustment required for the consolidated "Cost of Sales" at 30 June 2020 in relation to this intra-group transaction?

Please provide a numerical value without a sign ($, + or -), punctuation, or space.