negative ending inventory

[RWG1950]

Regarding the Sub-S income statement example in TTB 19-18.
Can anyone explain how there can be a negative figure in ending inventory in the COGS calculation ?
This may be covered somewhere in the line-by-line example of the material, but I am unable to locate it.
Thanks for comments.

[Uncle Sam]

The ending inventory is not negative. It's shown in brackets to reduce the total Cost of Goods Sold.

[RWG1950]

Thanks Sam. Can't believe I misinterpreted this.