using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(RetonaValorMonetario("2000,955"));

    }

    public static string RetonaValorMonetario(string valor)

    {

        try

        {

            valor = Regex.Replace(Regex.Replace(valor.ToString(), "\\.", ""), ",", ".");

            var valorSplit = valor.Split('.');

​

            if(valorSplit.Length > 1)

            {

                valorSplit[1] = valorSplit[1].Length > 2 ? valorSplit[1].Substring(0, 2) : valorSplit[1];

                valor = valorSplit[0] + "." + valorSplit[1];

            }

            else

                valor = valorSplit[0];

        }

        catch { }

​

        return valor;

    }

}