Is buying stock after overhearing an unannounced takeover insider trading?

"5. While having dinner at a Manhattan restaurant, you overhear two investment bankers at the next table. They are discussing the takeover of Bellamco Industries by Gildmart Corp., a deal that has not yet been announced. You have been thinking about buying Bellamco stock for a while, so the next day you buy 500 shares for $30 each. Two weeks later, Gildmart announces its acquisition of Bellamco at a price of $45 per share. Have you fairly earned a profit, or are you guilty of insider trading? What’s wrong with insider trading? (Information)"