using System;

using System.Collections.Generic;

​

​

class PhoneBook

{

    Dictionary<string, string> subs = new Dictionary<string, string>();

    public void addSub(string name, string number)

    {

        if (this.subs.ContainsKey(name)) {

            Console.WriteLine("{0} already has a number!", name);

        } else {

            this.subs.Add(name, number);

        }

    }

    public void printAll() {

        foreach(KeyValuePair<string, string> kvp in this.subs)

        {

            Console.WriteLine("{0} phone is: {1}", kvp.Key, kvp.Value);

        }

    }

    public List<KeyValuePair<string, string>> getSubsWithPhone(string phone) {

        List<KeyValuePair<string, string>> subs = new List<KeyValuePair<string, string>>();

        foreach(KeyValuePair<string, string> kvp in this.subs)

        {

            if (kvp.Value == phone) {

                subs.Add(kvp);

            }

        }

        return subs;

    }

}

public class Program

{

    public static void Main()

    {

        PhoneBook instance = new PhoneBook();

        instance.addSub("Ivan", "+79998887766");

        instance.addSub("Not Ivan", "+78887776655");

        instance.addSub("Hot Ivan", "+77776665544");

        instance.addSub("Same as Hot Ivan", "+77776665544");

        instance.addSub("Ivan", "+76665554433");

        instance.printAll();

        Console.WriteLine("Type phone to search:");

        string requiredPhone = Console.ReadLine();

        List<KeyValuePair<string, string>> subsWithPhone = instance.getSubsWithPhone(requiredPhone);

        Console.WriteLine("Found {0} sub(s) with phone {1}", subsWithPhone.Count, requiredPhone);

        foreach(KeyValuePair<string, string> kvp in subsWithPhone)

        {

            Console.WriteLine(kvp.Key);

        }

    }

}