//
// A random set of integers of size n
// 

import java.util.Random;

public class RandomSet {
    
    private int[] v;
    private int size;
    private int capacity;
    private Random random;
    
    public RandomSet(int n){
	size     = 0;
	capacity = n;
	v        = new int[n];
	random   = new Random();
    }

    private int uniform(int N) {
        return random.nextInt(N);
    }

    private void swap(int[] v,int i,int j){int temp = v[i];v[i] = v[j]; v[j] = temp;}
    
    public void add(int e) throws RandomSetException {
	if (size == capacity) throw new RandomSetException("overflow");
	v[size] = e;
	size++;
	swap(v,uniform(size),size-1);
    }
    //
    // add an element e, assumed to be unique
    //

    public int delete() throws RandomSetException {
	if (size == 0) throw new RandomSetException("underflow");
	int i = uniform(size);
	int e = v[i];
	size--;
	swap(v,i,size);
	return e;
    }
    //
    // select randomly an element e, delete e from the set, then return e
    //

    public int select() throws RandomSetException {
	if (size == 0) throw new RandomSetException("uderflow");
	int i = uniform(size);
	int e = v[i];
	return e;
    }
    //
    // select randomly an element e, then return e
    //
       

    public int size(){return size;}

    public String toString(){
	String s = "{";
	if (size > 0) s = s + v[0];
	for (int i=1;i<size;i++) s = s +"," + v[i];
	return s + "}";
    }


    public static void main(String[] args) throws RandomSetException {
	int n = Integer.parseInt(args[0]);
	RandomSet S = new RandomSet(n);

	for (int i=0;i<n;i++){
	    S.add(i);
	    System.out.println("  " + S);
	}
	
	for (int i=0;i<n;i++){
	    System.out.print(S.delete() + " ");
	    System.out.println(S);
	}

    }
}