using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var cities = new Dictionary<string, string>(){

            {"UK", "London, Manchester, Birmingham"},

            {"USA", "Chicago, New York, Washington"},

            {"India", "Mumbai, New Delhi, Pune"}

        };

​

        Console.WriteLine("Total Elements: {0}", cities.Count);

        cities.Remove("UK"); // removes UK 

        //cities.Remove("France"); //throws run-time exception: KeyNotFoundException

​

        if(cities.ContainsKey("France")){ // check key before removing it

            cities.Remove("France");

        }

        Console.WriteLine("Total Elements: {0}", cities.Count);

​

        cities.Clear(); //deletes all elements

        Console.WriteLine("Total Elements after Clear(): {0}", cities.Count);

​

    }

}