#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

size_t findLargestPalindrome(const string& s, size_t begin, size_t end) {
	size_t result = 0;
	for (size_t i = begin; i < end; ++i) {
		for (size_t k = i + 1; k <= end; ++k) {
			bool isPalindrome = true;
			for (size_t m = 0; m < (k - i) / 2; ++m) {
				if (s[i + m] != s[k - 1 - m]) {
					isPalindrome = false;
					break;
				}
			}
			if (isPalindrome) {
				result = max(result, k - i);
			}
		}
	}
	return result;
}

int main() {
	string s;
	cin >> s;
	size_t result = 0;
	for (size_t sep = 1; sep <= s.size() - 1; ++sep) {
		result = max(result, findLargestPalindrome(s, 0, sep));
		result = max(result, findLargestPalindrome(s, sep, s.size()));
	}
	cout << result << endl;
	return 0;
}