using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        List<string> names = new List<string>();

        names.Add("Afganistan");

        names.Add("Istanbul");

        names.Add("Pakistan");

        names.Add("Bulgaristan");

        names.Add("İran");

        names.Add("Yunanistan");

        var t = names.FindAll(q => q.IndexOf("istan", System.StringComparison.InvariantCultureIgnoreCase) >= 0);

        foreach (var s in t)

            Console.WriteLine(s);

        Console.WriteLine();

        t = t.OrderBy(q => q.IndexOf("istan", System.StringComparison.InvariantCultureIgnoreCase)).ToList();

        foreach (var s in t)

            Console.WriteLine(s);

    }

}