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 left1 = i;
            int right1 = i;
            while (left1 >= 0 && right1 < arr.length && arr[left1] == arr[right1] && !(left1 == 0 && right1 == arr.length - 1)) {
                max = Math.max(right1 - left1 + 1, max);
                left1--;
                right1++;
            }
            left1 = i;
            right1 = i + 1;
            while (left1 >= 0 && right1 < arr.length && arr[left1] == arr[right1] && !(left1 == 0 && right1 == arr.length - 1)) {
                max = Math.max(right1 - left1 + 1, max);
                left1--;
                right1++;
            }
        }
        System.out.println(max);
    }
}