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

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("Yes")
#define p_no() p("No")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

bool is_palin(string s){
    string t = s;
    reverse(ALL(t));
    if(s==t){
        return true;
    }else{
        return false;
    }
}

bool is_there_palin(string s, ll len){
    ll L = s.size();
    FOR(i, 0, L-len+1){
        string sub = s.substr(i, len);
        if(is_palin(sub)){
            return true;
        }
    }
    return false;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    string s;
    cin >> s;
    ll L = s.size();

    for(int len=L-1; len>=1; len--){
        if(is_there_palin(s, len)){
            p(len);
            return 0;
        }
    }
    
    return 0;
}