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

using namespace std;

int check(string s, int a, int b) {
	int len = b - a + 1;
	while (a <= b) {
		if (s[a] != s[b]) {
			return 0;
		}
		a++;
		b--;
	}

	return len;
}

int main() {
	string s;

	cin >> s;

	int n = s.size();
	int max_len = 0, n_len;

	for (int i = 0; i < n; i++) {
		for (int j = i; j < n; j++) {
			n_len = check(s, i, j);
			if (n_len < n) {
				max_len = max(max_len, n_len);
			}
		}
	}

	cout << max_len << endl;
	return 0;
}