/* package whatever; // don't place package name! */

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

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String s="babad";
		 int n = s.length();
        String ans ="";
        for(int i=0;i<n;i++){
            for(int j=i;j<n;j++){
                String ts = s.substring(i,j+1);
                if(isPalindrome(ts) && ts.length()>ans.length()){
                   ans =ts;
                }
            }
        }
       System.out.println(ans);
    
	}
	
	 static public boolean isPalindrome(String s){
        int l=0,r=s.length()-1;
        while(l<=r){
            if(s.charAt(l) != s.charAt(r)){
                return false;
            }
            l++;
            r--;
        }
        return true;
    }
}