using System;

using System.Text;                  

public class Program

{

    public static void Main()

    {

        Console.WriteLine(DoubleChar("String"));

    }

    public static string DoubleChar(string str) 

    {

      StringBuilder sb = new StringBuilder();

        for(int i=0;i<str.Length;i++){

            sb.Append(str[i],2);

        }

        return sb.ToString();

    }

}