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

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
        Map<Integer, String> hm = new HashMap<>();
        hm.put(0, "zero");
        hm.put(1, "one");
        
        for (Integer key : hm.keySet()) {
            System.out.println(key);
            System.out.println(hm.get(key));
        }
    }
}