import java.util.*;
public class TreeMapDemo
{
public static void main(String[] args)
{
TreeMap<String, Integer> tm = new TreeMap<>();
tm.put("Anand", 20);
tm.put("Mary", 20);
tm.put("Ravi", 21);
tm.put("John",19);
System.out.println("Contents: "+tm);
System.out.println();
Set<String> keys = tm.keySet();
for(String k: keys)
System.out.println(k+" -- "+tm.get(k));
System.out.println();
Set<Map.Entry<String, Integer>> entries = tm.entrySet();
for(Map.Entry<String,Integer> each: entries)
System.out.println(each.getKey()+" -- "+each.getValue());
System.out.println();
}
}