package newpta;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
public class Find 
{
    public static void main(String[] args) 
    {
        ArrayList<Words> list = new ArrayList<Words>();
        Scanner input = new Scanner(System.in);
        String str1 = input.nextLine();
        String kg[]=str1.split("\\s+");
        for(String s:kg)
        {
            Words words=new Words(s);
            list.add(words);    
        }
        Collections.sort(list, new ByLength());
        System.out.println(list.get(list.size()-1).getWord());
    }
}
class Words
{
    String word;
    Words(String word)
    {
        this.word=word;
    }
    public String getWord()
    {
        return word;
    }
    public int getLength()
    {
        return word.length();
    }
}
class ByLength implements Comparator<Words>
{
    @Override
    public int compare(Words o1, Words o2)
    {
        if(o1.getLength() == o2.getLength())
        {
            return 0; //返回0，表示人类o1与o2长度一样
        }else if(o1.getLength() > o2.getLength())
        {
            return 1; //返回正数，表示01大于o2长度
        }else
        {
            return -1; //返回负数，表示o1年龄小于o2长度
        }
    }
}