Denys Zhadanov, the 25-year-old marketing manager of Readdle, a Ukrainian app-development company, peers out from behind the wheel of his gleaming white Volkswagen Tiguan, vainly searching for a landmark. We’re lost somewhere off Akademika Filatova street, a long four-lane boulevard cutting through Odessa, a sprawling Black Sea port of a million people in southern Ukraine. Christmas trimmings provide a welcome splash of color: Ukraine celebrates the holiday on January 7th, but a month later many decorations remain, including a giant gorilla in a Santa suit. His older brother, Igor Zhadanov, 30, points the way.