using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var numbers = new List<int>(){1,2,3,4,5};

        // cannot modify list element using foreach iteration

        // foreach(var number in numbers)

        // {

        //      number += number + 1;

        // }

        foreach (var number in numbers)

        {

            Console.Write(number);

        }

        Console.WriteLine();

        for (var i = 0; i<numbers.Count; i++)

        {

            numbers[i] += 1;

        }

        foreach (var number in numbers)

        {

            Console.Write(number);

        }

        Console.WriteLine();

        Console.WriteLine("Hello World");

    }

}