import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        char[] arr = sc.next().toCharArray();
        int max = 0;
        for (int i = 0; i < arr.length; i++) {
            int left = i;
            int right = i;
            int length = -1;
            while (left >= 0 && right < arr.length) {
                if (arr[left] == arr[right]) {
                    length += 2;
                }
                left--;
                right++;
            }
            max = Math.max(max, length);
            left = i;
            right = i + 1;
            length = 0;
            while (left >= 0 && right < arr.length) {
                if (arr[left] == arr[right]) {
                    length += 2;
                }
                left--;
                right++;
            }
            max = Math.max(max, length);
        }
        System.out.println(max);
    }
}