A company has the following data:

Cash dividends paid in 2020	400
Dividends payable balance at December 31, 2020	200
Net income for 2020	2,400
Retained earnings at December 31, 2019	15,000
Retained earnings at December 31, 2020	16,100

The company had a single adjustment to beginning retained earnings for a correction of error in a prior period's net income.

If the company's tax rate is 30% in all years, what was the pre-tax amount of the adjustment to beginning retained earnings?