#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>
#include <list>
#include <tuple>
#include <bitset>
#include <ciso646>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

inline bool cheak(ll x, ll y, ll xMax, ll yMax){ return x >= 0 && y >= 0 && xMax > x && yMax > y; }
inline ll toInt(string s) { ll v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
template<class T> inline T sqr(T x) { return x*x; }

#define For(i,a,b)	for(ll (i) = (a);i < (b);(i)++)
#define rep(i,n)	For(i,0,n)
#define rFor(i,a,b)	for(ll (i) = (a-1);i >= (b);(i)--)
#define rrep(i,n)	rFor(i,n,0)
#define clr(a)		memset((a), 0 ,sizeof(a))
#define mclr(a)		memset((a), -1 ,sizeof(a))
#define all(a)		(a).begin(),(a).end()
#define sz(a)		(sizeof(a))

const int dx[8] = { 1, 0, -1, 0, 1, 1, -1, -1 }, dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 };
const ll mod = 1e9 + 7;
const ll INF = 1e9 + 2;

bool ok(string s){
	auto t = s;
	reverse(all(t));
	return s == t;
}

int main(){
	string s;
	cin >> s;

	int d[51][51];
	clr(d);
	queue<P> q;

	rep(i, s.size()){
		for(int j = 1;i + j <= s.size();j++){
			auto t = s.substr(i, j);
			if (ok(t)){
				d[i][j] = t.size();
				if (j != s.size())
				q.push(P(j, d[i][i+j]));
			}
		}
	}
	int ans = 0;
	int memo[51][51];
	clr(memo);
	while (q.size()){
		int i	= q.front().first;
		int res = q.front().second;
		q.pop();
		if (memo[i][res] != 0)continue;
		memo[i][res] = 1;
		if (i == s.size()){
			ans = max(ans, res);
		}
		for (int j = 1; i + j <= s.size(); j++){
			if (d[i][j]){
				q.push(P(i+j, max(res, d[i][j])));
			}
		}
	}

	cout << ans << endl;
	return 0;
}