Envío 2080

Código

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(new BufferedReader(new InputStreamReader(System.in)));

		String s = sc.nextLine();
		int largest = 0, len = s.length();

		for (int i = 0; i < len; i++) {
			if (s.charAt(i) == s.charAt(len - i - 1)) {
				largest++;
			} else {
				break;
			}
		}
		System.out.println(largest == len ? len - 1 : largest);

	}
}