using System;

public class Program

{

    public static void Main(string[] args)

    {

        string str ="Enterprise Content Management is all we do";

        string[]  words = str.Split(' ');

        string longestword= "";

        int i=0;

foreach(string word in words){

         if (word.Length > i) { 

             longestword=word; 

            i = word.Length;                   

          }

        }

        Console.WriteLine(longestword);

          }

}

​