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

public class Main {
    static HashMap<Character, Integer> change = new HashMap<>();
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        char[] values = sc.next().toCharArray();
        int max = 0;
        for (int i = 0; i < values.length; i++) {
            int left = i;
            int right = i;
            while(left >= 0 && right < values.length && values[left] == values[right] && right - left + 1 < values.length) {
                max = Math.max(max, right - left + 1);
                left--;
                right++;
            }
            left = i;
            right = i + 1;
            while(left >= 0 && right < values.length && values[left] == values[right] && right - left + 1 < values.length) {
                max = Math.max(max, right - left + 1);
                left--;
                right++;
            }
        }
        System.out.println(max);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}