package tests;

import java.util.Hashtable;

public class Test {
  public static void main(String[] args) {
    Hashtable ht = new Hashtable();
    ht.put("1", "2");
    ht.put("2", "3");
    ht.put("3", "4");
    ht.put("4", "2");
    
    if(ht.contains("1")){
      System.out.print("1");
    }
    if(ht.contains("2")){
      System.out.print("2");
    }
    if(ht.contains("3")){
      System.out.print("3");
    }
    if(ht.contains("4")){
      System.out.print("4");
    }
  }
}