Brennan a farmer orders a large box of ladybugs to control pests in his greenhouse. To make sure that he was shipped as many ladybugs as he ordered, he decides to figure out approximately how many ladybugs there are in the box. He catches 30 ladybugs, marks them with special paint, and returns them to the box. Then a little while later, he catches 390 ladybugs and counts 13 marked ladybugs among them. To the nearest whole number, what is the best estimate for the ladybug population?