#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll =  long long ;
using P = pair<int,int> ;
using pll = pair<ll,ll>;
constexpr int INF = 1e9;
constexpr ll LINF = 1e18;
constexpr int MOD = 1000000007;

int main(){
    string s;
    cin >> s;
    int n = s.size();
    int mx = 0;
    for(int i=0;i<n;i++){
        for(int j=0;j+i<=n;j++){
            if(i==0 &&j==n) continue;
            string now = s.substr(i,j);
            string rev = now;
            reverse(rev.begin(),rev.end());
            if(now == rev) mx = max(mx,j);
        }
    }
    cout << mx << endl;
    return 0;
}