import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Random;

public class HashSetDemo {
    public static void main(String[] args) {
        ArrayList<Integer> al=new ArrayList<Integer>();
        for (int i = 0; i < 54; i++) {
            al.add(i);
        }
        
        
        
        HashSet<Integer> hs=new HashSet<Integer>();
        Random rd=new Random();
        for (int i = 0; i < 54;) {
            int k=rd.nextInt(54);
            
            if(hs.contains(al.get(k))){
                continue;
            }
            hs.add(al.get(k));

            i++;
        }
        
        
        
        Iterator<Integer> it=hs.iterator();
        while(it.hasNext()){
            System.out.println(it.next());
        }
    }
}