WASHINGTON — Ukraine collected $500 million more revenue than expected in the first three months of this year, the country’s Finance Minister Serhii Marchenko said, as Ukraine tries to better line its war coffers and reassure key partners. "Revenue mobilization is strong," Marchenko said at the U.S.-Ukraine Partnership Forum hosted by the U.S. Chamber of Commerce on April 15 in Washington D.C., where he spoke on a panel on financing Ukraine’s recovery. Big donors to Ukraine, including the Inte