B

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cmath>
#include <string>
#include <algorithm>
#include <vector>

using namespace std;


int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	ios::sync_with_stdio(false);
	string s;
	cin >> s;
	int n = s.size();
	int k = 0;
	int o = 1;
	int max = 1;
	for (int i = 0; i < n; ++i) {
		k = 0;
		int z = i;
		for (int j = n - 1; j >= i; --j) {
			if (s[i] != s[j]) {
				o = 0;
				i -= k;
				k = 0;
			}
			else {
				o = j + k;
				++i;
				++k;
			}
		}
		i = z;
		if (o - i + 1 > max) {
			max = o - i + 1;
		}
	}
	cout << max;
}