#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,n) for(int (i)=0;(i)<(n);++(i))
#define FOR(i,a,b) for(int (i)=(a);(i)<(b);++(i))
#define EACH(e,v) for(auto& e:v)
#define ALL(v) (v).begin(),(v).end()
#define SORT(v) sort(ALL(v))
#define RSORT(v) sort((v).rbegin(),(v).rend())
#define PERM(v) SORT(v);for(bool c##p=1;c##p;c##p=next_permutation(ALL(v)))
#define UNIQUE(v) SORT(v);(v).erase(unique(ALL(v)),(v).end())
template<typename A,typename B> inline bool chmax(A &a,const B &b){if(a<b){a=b;return 1;}return 0;}
template<typename A,typename B> inline bool chmin(A &a,const B &b){if(a>b){a=b;return 1;}return 0;}
// #define int long

const int MOD = (int)1e9 + 7;
const int INF = 1 << 30;
const ll INFF = 1LL << 62;

// 下にy, 右にx
enum {R, U, L, D};
const int dx[] = {1,  0, -1, 0};
const int dy[] = {0, -1,  0, 1};

template<int mod, int base=10007>
struct RollingHash {
    vector<ll> hsh, pwr;
    ll umod(ll n) { return (n % mod + mod) % mod; }
    RollingHash(const string &s) {
        int sz = (int)s.size();
        hsh.assign(sz + 1, 0);
        pwr.assign(sz + 1, 0);  pwr[0] = 1;
        for (int i = 0; i < sz; ++i) {
            hsh[i + 1] = umod(hsh[i] * base + s[i]);
            pwr[i + 1] = umod(pwr[i] * base);
        }
    }
    // [l, r)
    ll get(int l, int r) {
        return umod(hsh[r] - hsh[l] * pwr[r - l]);
    }
    // h1 <- h2
    ll join(ll h1, ll h2, int h2_sz) {
        return umod(h1 * pwr[h2_sz] + h2);
    }
};
using RH1 = RollingHash<(int)1e9 + 7>;
using RH2 = RollingHash<(int)1e9 + 9>;
using RH = pair<RH1, RH2>;
using H = pair<ll, ll>;
RH init(const string &s) { return make_pair(RH1(s), RH2(s)); }
H get(RH &rh, int l, int r) { return make_pair(rh.first.get(l, r), rh.second.get(l, r)); }
H join(RH &rh, ll h1, ll h2, int h2len) {
    return make_pair(rh.first.join(h1, h2, h2len), rh.second.join(h1, h2, h2len));
}

signed main() {

    string S2;
    cin >> S2;

    int N2 = S2.size();
    string S;
    for (int i = 0; i < N2; ++i) {
        S += S2[i];
        if (i != N2 - 1) S += "a";
    }

    int N = S.size();
    string T(S);
    reverse(T.begin(), T.end());
    
    RH S_rh = init(S);
    RH T_rh = init(T);

    // 中心cen, 腕の長さmが回文であるならtrue
    function<bool(int, int)> check = [&](int cen, int m) {
        if (cen + m + 1 > N) return false;
        H s = get(S_rh, cen, cen + m + 1);
        int cen_rev = N - 1 - cen;
        if (cen_rev + m + 1 > N) return false;
        H t = get(T_rh, cen_rev, cen_rev + m + 1);
        return (s == t);
    };

    ll res = 1;
    // i文字目を中心とする最長回文
    for (int i = 0; i < N; i++) {
        ll ok = 0, ng = N;
        while (abs(ok - ng) > 1) {
            ll mid = (ok + ng) / 2;
            if (check(i, mid)) {
                ok = mid;
            } else {
                ng = mid;
            }
        }
        // iが奇数なら偶数長の回文
        // iが偶数なら奇数長の回文
        // chmax(res, ok);
        if (i % 2 == 0) chmax(res, ok + 1);
        else chmax(res, ok);
    }
    cout << min<ll>(N2 - 1, res) << endl;

}