#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 l = 0; l < n; l++) {
		for (int r = l; r < n; r++) {
			int tmp = 0;
			for (int i = 0; l + i <= r - i; i++) {
				if (s[l + i] == s[r - i]) {
					tmp += l + i == r - i ? 1 : 2;
				}
			}
			ans = max(ans, tmp);
		}
	}

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