using System;

public class Program

{

    public static void Main()

    {

        double tInt = 1.55555;

        var tt = test(tInt);

        Console.WriteLine(tt);

    }

    static object test(double tDouble)

    {

        string tData = tDouble.ToString();

        var tIndex = tData.LastIndexOf('.');

        return tData.Substring(0,tIndex+3);

    }

}