were distinguished by different stamps that were first affixed to and then printed on old Czechoslovak koruna banknotes. New czech and slovak coins replaced old ones during 1993. On January 1, 2009, Slovakia adopted the euro as its currency with an exchange rate of 30.126 SK/€, and the €2 commemorative coin for 2009, Slovakia's first, featured the 20th anniversary of the Velvet Revolution in remembrance of the common struggle of the Czechoslovaks for democracy. By a quirk of fate, the welcoming speech on the behalf of the European Union on the occasion of Slovakia's entry to the eurozone was delivered by Mirek Topolánek, the prime minister of the presiding country, the Czech Republic, naturally in his native language, but the other guest speakers used English. The Czech Republic continues to use the Czech koruna, or crown. International law Neither the Czech Republic nor Slovakia sought recognition as the sole successor state to Czechoslovakia. This can be contrasted to the dissolution of the Soviet Union, when the Russian Federation was recognised as successor state to not only the Russian SFSR but also the Soviet Union itself. Therefore, Czechoslovakia's membership in the United Nations ceased upon the dissolution of the country, but on January 19, 1993, the Czech Republic and Slovakia were admitted as new, separate states. With respect to other international treaties, the Czechs and the Slovaks agreed to honour the treaty obligations of Czechoslovakia. The Slovaks transmitted a letter to the Secretary General of the United Nations on May 19, 1993, to express their intent to remain a party to all treaties signed and ratified by Czechoslovakia and to ratify treaties signed but not ratified before dissolution of Czechoslovakia. The letter acknowledged that under international law, all treaties signed and ratified by Czechoslovakia would remain in force. For example, both countries are recognised as signatories of the Antarctic Treaty from the date that Czechoslovakia had signed the agreement in 1962. Both countries have ratified the Vienna Convention on Succession of States in respect of Treaties, but it was not a factor in the dissolution of Czechoslovakia since it did not come into force until 1996. Aftermath Economy The dissolution had some negative impact on the two economies, especially in 1993, as traditional links were severed to accommodate the bureaucracy of international trade, but the impact was considerably less than expected by many people. A customs union between the Czech Republic