Task: Explanation
Input (English): Międzymorze (] ), known in English as Intermarium, was a plan, pursued after World War I by Polish leader Józef Piłsudski, for a federation, of Central and Eastern European countries. Invited to join the proposed federation were the Baltic states (Lithuania, Latvia, Estonia), Finland, Belarus, Ukraine, Hungary, Romania, Yugoslavia and Czechoslovakia. Question: What was the planned, first devised by Raivis Zeltits, to form a federation of Central and Eastern European countries after World War I? Answer: Intermarium
Output (English): Międzymorze  , known in English as Intermarium, was a plan, pursued after World War I by Polish leader Józef Piłsudski, for a federation, of Central and Eastern European countries.