#include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
//#include "toollib.h"
#define INT_MAX 2147483647
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#pragma warning (disable:4018)

using namespace std;
typedef long long int lint;

typedef struct {
	int x;
	int y;
}coordinate;

//***** Main Program *****

//最大公約数を求める

int hoge1(string S, int p) {
	int ret = 1;
	for (int i = 1; i <= min(p, (int)S.length() - p - 1); i++) {
		if (S[p + i] == S[p - i]) ret+=2;
		else break;
	}
	if (ret == S.length()) ret -= 2;
	return ret;
}

int hoge2(string S, int p) {
	int ret = 0;
	for (int i = 0; i <= min(p, (int)S.length() - p - 2); i++) {
		if (S[p - i] == S[p + 1 + i]) ret += 2;
		else break;
	}
	if (ret == S.length()) ret -= 2;
	return ret;
}

int main() {
	string S;
	cin >> S;
	int ret = 0;
	Loop(i, S.length()) ret = max(ret, hoge1(S, i));
	Loop(i, S.length() - 1) ret = max(ret, hoge2(S, i));
	cout << ret << endl;
	return 0;
}