import java.util.*;
/**
 * Created by leon on 1/23/18.
 */
public class PhoneBook {
    private String phoneNumber;
    private String name;
    private Map<String,String> input;

 

    public PhoneBook(){
        input = new TreeMap<String,String>();
    }

    public void display(){
        
        for(Object keyValue:input.keySet()){
            System.out.println("Key: " + keyValue + ". Value: " + input.get(keyValue));
            }
    }

    public String remove(String name){
        return input.remove(name);
    }

    public void AddInput(String name,String phoneNumber){
        input.put(name,phoneNumber);
    }

    public String lookup(String name){
        String value = input.get(name);
        return value;
    }

    public String reverseLookup(String name,String phoneNumber){
        String value = "";
        if(input.containsValue(phoneNumber)){
            value = phoneNumber;
        }
        return value;
    }
}