/* package whatever; // don't place package name! */

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

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		ArrayList<Integer> list = new ArrayList<>();
		list.add(1);
		list.add(2);
		list.add(3);
		list.add(4);
		
		Iterator it = list.iterator();
		
		while(it.hasNext()){
			System.out.print(it.next() + " ");
		}
		System.out.println();
	}
}