import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import java.util.Set;

 public class zengzhiwei {

     public static void main(String agrs[]) {

         System.out.println("hello world!");

         Map<String, String> m = new HashMap<String, String>();

         m.put("zengzhiwei", "zzw");

         m.put("zengzhijie", "zzj");

         Set<String> s = m.keySet();

         Iterator<String> itr = s.iterator();

         while(itr.hasNext()) {

             Object o = itr.next();

             System.out.println(m.get(o));

         }

     }

 }