#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;

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

    // input
    string s;
    cin >> s;
    ll N = s.size();
    
    ll ans = 1;
    FOR(l, 0, N){
        FOR(r, l+1, N){
            ll erase = 0;
            ll R = (r-l+1)/2;
            FOR(i, 0, R){
                if(s[l+i]!=s[r-i]) erase += 2;
            }
            ll len = r-l+1 - erase;
            ans = max(ans, len);
        }
    }

    p(ans);
    
    return 0;
}