using System;

using System.IO;

using System.Data;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        string s = "sahadev_Jadi sahadevJadi";

        string result = update(s);

        Console.WriteLine(result);

    }

    public static string update(string s){

        string result ="";

       char [] array= s.ToCharArray();

        string previous=null;

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

            var add=array[i].ToString();

            int ascii= (int)array[i];

            if(i==0){

              previous= array[i].ToString();

            }

            if(previous!=null && previous=="_" && add!="_"){

                add=array[i].ToString().ToUpper();

            }

            else if(ascii>=65 && ascii<=90){

                add="_"+array[i].ToString().ToLower();

            }

            if(array[i].ToString()!="_"){

                result+=add;

            }

            if(i!=0)previous= array[i].ToString();

        }

        return result;

    }

}