#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>

using namespace std;

int main() {
	string s;
	cin >> s;
	int n = s.size();

	int ans = 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;
			}
		}
		ans = max(ans, tmp);

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

	cout << ans << endl;
	return 0;
}