import java.io.*;
import java.util.*;

public class PC {
    public static void main(String[] args) throws FileNotFoundException {

        Scanner io = new Scanner(new File("src/t.txt"));
        int word=0;
        String x ="";
        while(io.hasNext())
        {
            String lo = io.next();
            if(lo.equals("E-N-D"))
                break;
            if(word<lo.length())
            {
                word = lo.length();
                x = lo;
            }

        }
        System.out.print(x.toLowerCase());

    }


}