/*
ID: jennife2
LANG: JAVA
TASK: calfflac
*/

import java.io.*;

public class calfflac{

	public static int ops = 0;
	public static void main(String[] args) throws IOException{
		
		BufferedReader console = new BufferedReader(new FileReader("calfflac.in"));
		BufferedWriter out = new BufferedWriter(new PrintWriter(new FileWriter("calfflac.out")));
		String s = ""; // string to be handled
		String read = "";
		int[] st = new int[20000];
		
		int stc = 0;
		int counter = 0;
		
		while(console.ready()){
			String newline = console.readLine();
			read+=newline+"\n";
			for(int i=0;i<newline.length();i++){
				if ((int)newline.charAt(i)>96&&(int)newline.charAt(i)<123||(int)newline.charAt(i)>64&&(int)newline.charAt(i)<91){
					s += newline.charAt(i);
					st[stc] = counter;
					//System.out.println(newline.charAt(i)+","+counter+" ");
					stc++;
				}
				counter++;
			}
			counter++;
		}
		//System.out.print(s);
		s = s.toUpperCase();
		int longest = 0;
		int posLong = 0; // start position of longest palindrome
		int z = 1;
		
		// odd length palindromes
		for(int i=0; i<s.length();i++){
			for(z = 1;i-z>=0&&i+z<s.length()&&s.charAt(i-z)==s.charAt(i+z);z++); // loop through building pal
			// z will be one too long
			if ((z-1)*2+1>longest){
				longest = (z-1)*2+1;
				posLong = i-(z-1);
			}
		}
		// even length palindromes
		for(int i=0; i<s.length();i++){
			for(z = 1;i-z+1>=0&&i+z<s.length()&&s.charAt(i-z+1)==s.charAt(i+z);z++); // loop through building pal
			// z will be one too long
			if ((z-1)*2>longest||(z-1)*2==longest&&i-(z-1)+1<posLong){
				longest = (z-1)*2;
				posLong = i-(z-1)+1;
			}
		}
		
		if (longest>0){
			out.write(longest+"\n"+read.substring(st[posLong],st[posLong+longest-1]+1)+"\n");
		}
		else{
			out.write("0\n\n");
		}
		out.close();
		System.exit(0);
	}
}