A company projects that next year's sales will grow $15\%$ and ROA $($net income divided by the previous year's total assets$)$ is constant at $11\%,$ but long$-$term debt and equity do not change with sales automatically $($except for the new retained earnings$).$ The current year's total assets and accounts payable are $$10000$ and $$600.$ Accounts payable usually grow at the same rate as sales. The company's plowback ratio is always $90\%.$ Assuming that total assets must grow at the same speed as sales, what is next year's external financing need $($round to the closest whole number and the answer could be negative$)?$