using System;

​

// Class to create analog for JS toFixed method

public static class AnalogForJStoFixed

{

    public static string toFixed(this double number, int decimals)

    {

        return number.ToString("N" + decimals);

    }

}

​

public class Program

{

    public static void Main()

    {

        string mystring = "+91801929497";

       mystring = mystring.Substring(mystring.Length-10);

        Console.WriteLine(mystring);

        Console.WriteLine(mystring);

    }

}