using System;

using System.Text.RegularExpressions;

public class Prgm1

{

    public static void removeLeadingZeros(string str)

    {

        string regex="^0+(?!$)";

        str=Regex.Replace(str,regex,"");

        Console.WriteLine(str);

    }

    public static void Main(string[] args)

    {

       string str="000B123";

       removeLeadingZeros(str); 

    }

}