#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

bool isPalindromic(string &s){
    int n = (int)s.size();
    for(int i = 0; i < n / 2; ++i)
        if(s[i] != s[n - i - 1]) return false;
    return true;
}

int main(){
    string s; cin >> s;
    int n = sz(s);
    for(int l = n - 1; l >= 1; --l){
        rep(i, n - l + 1){
            string t = s.substr(i, l);
            if(isPalindromic(t)){
                cout << l << endl;
                return 0;
            }
        }
    }
}