using System.Security.Cryptography.X509Certificates;

namespace UmlautsExtentions
{
    internal class Program
    {
        static void Main(string[] args)
        {
            string input = "Ueber ein leben hinaus, aeßert man sich nicht.";
            Console.WriteLine(input.Umlauts());
        }
    }
    static class UmlautsExtentions
    {
        public static string Umlauts(this string input)
        {
            return input.Replace("ae","ä").Replace("oe","ö").Replace("ue","ü").Replace("Ae", "Ä").Replace("Oe", "Ö").Replace("Ue", "Ü");
        }
    }
}