import java.io.FileReader;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class FileAnalyzer
{
   /**
      @param inputFileName the name of the input file
   */
   public static String longestWord(String inputFileName)
      throws FileNotFoundException
   {
      FileReader fr = new FileReader(inputFileName);
      String longestWord = "";
      String currentWord = "";

      try
      {
         while(true)
         {
            int ch = fr.read();

            if(ch == -1){break;}
            if(Character.toString(((char)ch)).matches("[, \n]"))
            {
               if(longestWord.length() < currentWord.length())
               {
                  longestWord = currentWord;
                  currentWord = "";
               }
               else
               {
                  currentWord = "";
               }
            }
            else{currentWord += (char)ch;}
         }
      }
      catch(Exception e){}

      return longestWord;
   }
}