import java.util.*;
import java.lang.*;
import java.io.*;

class Country {
	static final Set<String> EXISTING = new HashSet<String>();
	
	final String name;
	
	Country(String name) {
		if(EXISTING.contains(name))
			throw new IllegalArgumentException(name + " already exists!");
			
		this.name = name;
		EXISTING.add(name);
	}
	
	public static void main (String[] args) {
		Country oldSweden = new Country("Sweden");
		
		try {
			Country newSweden = new Country("Sweden");
		} catch(IllegalArgumentException iae) {
			System.out.println(iae.getMessage());
		}
	}
}