OPINION OF THE ECONOMIC AND SOCIAL COMMITTEE on the agreement in the form of an Exchange of Letters amending the Exchange of Letters between the European Economic Community (' the Community' ) and Hungary concerning transit signed in Brussels on 16 December 1991, and the agreements in the form of an Exchange of Letters replacing the Exchange of Letters between the European Economic Community (' the Community' ) and Hungary on land transport infrastructure signed in Brussels on 16 December 1991