Ukrainian President Volodymyr Zelenskyy surprised graduates Thursday morning at Johns Hopkins University's commencement ceremony. Zelenskyy appeared via a virtual livestream to speak to the graduating class. He told the graduates that time is the most valuable resource, not oil, uranium or lithium. "Every person eventually realizes that time is the most valuable resource on the planet -- not oil, or uranium, not lithium or anything else, but time. Time. The very flow of time convinces us of these. Some people realize this sooner, and these are the lucky ones. Others realize it too late," Zelenskyy said.