#include<iostream>
#include<cstdio>
#include<cstring>
#include <cstdlib>  
#include <cmath>   
#include<cctype>
#include<string>
#include<set>
#include<iomanip>
#include <map>
#include<algorithm>
#include <functional>
#include<vector>
#include<climits>
#include<stack>
#include<queue>
#include <deque>
#include <climits>
#include <typeinfo>
#include <utility> 
#define all(x) (x).begin(),(x).end()
#define rep(i,m,n) for(int i = m;i < n;++i)
#define pb push_back
#define fore(i,a) for(auto &i:a)
#define rrep(i,m,n) for(int i = m;i >= n;--i)
#define INF INT_MAX/2
using namespace std;
using ll = long long;
using R = double;
const ll MOD = 1e9 + 7;
const ll inf = 1LL << 50;
struct edge { ll from; ll to; ll cost; };


int main() {
	string s;
	cin >> s;
	int sz = s.size();


	for (int i = sz-1; i >= 1; --i) {
		for (int j = 0; j + i <= sz ; ++j) {
			string s1 = "";
			string s2 = "";
			for (int k = j;  k <= j + i - 1; ++k) {
				s1 += s[k];
			}
			for (int k = j + i - 1; k >= j; --k) {
				s2 += s[k];
			}
			if (s1 == s2) {
				cout << i << endl;
				return 0;
			}
		}
	}
	return 0;
}