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


public class Main_yukicoder588 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		char[] s = sc.next().toCharArray();
		int n = s.length;

		int max = 0;
		for (int i = 0; i < n; i++) {
			int tmp = 1;
			for (int j = 1; i - j >= 0 && i + j < n; j++) {
				if (s[i - j] == s[i + j]) {
					tmp += 2;
				}
			}

			max = Math.max(max, tmp);
		}

		for (int i = 0; i < n; i++) {
			int tmp = 0;
			for (int j = 0; i - j >= 0 && i + 1 + j < n; j++) {
				if (s[i - j] == s[i + 1 + j]) {
					tmp += 2;
				}
			}

			max = Math.max(max, tmp);
		}

		pr.println(max);
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}