#include <bits/stdc++.h>
using namespace std;

#define REP(i,n) for(int i=0;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF INT_MAX/3
#define LINF LLONG_MAX/3
#define MP make_pair
#define PB push_back
#define EB emplace_back
#define ALL(v) (v).begin(),(v).end()
#define debug(x) cout<<#x<<":"<<x<<endl
#define debug2(x,y) cout<<#x<<","<<#y":"<<x<<","<<y<<endl
template<typename T>
ostream& operator<<(ostream& os,const vector<T>& vec){
    os << "[";
    for(const auto& v : vec){
        os << v << ",";
    }
    os << "]";
    return os;
}

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;

int main(){
    string s;
    cin>>s;
    int n=s.size();
    for(int i=n-1;i>=0;i--){
        for(int j=0;j+i<=n;j++){
            string ss = s.substr(j,i);
            string rs = ss;
            reverse(ALL(rs));
            if(ss==rs){
                cout << ss.size() << endl;
                return 0;
            }
        }
    }
}