Write a C# Sharp program to move the last two characters to the start of a given string of length at least two

using System;
namespace exercises
{
   class Program
    {       
        static void Main(string[] args)
        {
            Console.WriteLine(test("Hello"));
            Console.WriteLine(test("JS"));
            Console.ReadLine();
        }        
         public static string test(string s1)
         {
              return s1.Substring(s1.Length - 2) + s1.Remove(s1.Length - 2);
         }
  }
}