# include <iostream>
# include <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
# include <bitset>
# include <complex>
# include <numeric>
# include <tuple>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
constexpr int MOD = 1000000000 + 7;
constexpr int INF = 2000000000;
constexpr int HINF = INF / 2;
constexpr double DINF = 100000000000000000.0;
constexpr long long LINF = 9223372036854775807;
constexpr long long HLINF = 4500000000000000000;
const double PI = acos(-1);
int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
#define ALL(x)   (x).begin(),(x).end()
#define mp       make_pair
#define eb       emplace_back

int main(){
	string s;
	cin >> s;
	int ans = 1;
	for (int i = 0; i < s.size(); i++) {
		int count = 0;
		for (int j = 0;; j++) {
			if (i-j < 0 || i+j >= s.size())break;
			if (s[i + j] == s[i - j])count++;
		}
		ans = max(ans, (count-1)*2+1);
	}
	for (int i = 0; i < s.size(); i++) {
		int count = 0;
		for (int j = 0;; j++) {
			if (i - j < 0 || i + j + 1 >= s.size())break;
			if (s[i - j] == s[i + j + 1])count++;
		}
		ans = max(ans, count * 2);
	}
	cout << ans << endl;
}