#include <bits/stdc++.h>

using namespace std;

const long long M = 1e9 + 9;
const long long N = 237;
const int MAX = 4100000;
long long d[MAX];

vector <long long> hashs(string s) {
    vector <long long> h(s.size() + 1);
    for (int i = 0; i < (int) s.size(); ++i) {
        h[i + 1] = (h[i] * N + s[i]) % M;
    }
    return h;
}

long long hash_sub(vector <long long>& h, int l, int r) {
    long long res = h[r] - h[l] * d[r - l];
    res %= M;
    if (res < 0) res += M;
    return res;
}

vector <int> pal(string s) {
    int n = s.size();
    vector <long long> hs = hashs(s);
    reverse(s.begin(), s.end());
    auto rhs = hashs(s);
    vector <int> res(n + 1);
    for (int i = 0; i < n + 1; ++i) {
        int left = 0, right = min(i, n - i) + 1;
        while (right - left > 1) {
            int mid = (left + right) / 2;
            (hash_sub(hs, i - mid, i + mid) == hash_sub(rhs, n - i - mid, n - i + mid) ? left : right) = mid;
        }
        res[i] = left;
    }
    return res;
}

vector <int> trans(vector <int> ps) {
    int t = 0;
    vector <int> seq = {t};
    for (int i = 1; i < (int) ps.size(); ++i) {
        if (i - ps[i] <= t) {
            t = i;
            seq.push_back(t);
        }   
    }
    return seq;
}

int main() {
    d[0] = 1;
    for (int i = 0; i < MAX; ++i) {
        d[i + 1] = d[i] * N % M;
    }
    string s;
    cin >> s;
    auto ps = pal(s);
    auto ts = trans(ps);
    reverse(ps.begin(), ps.end());
    auto rts = trans(ps);
    int ans = s.size();
    reverse(rts.begin(), rts.end());
    int ptr = 0;
    for (int x : rts) {
        int temp = s.size() - x;
        while (ptr + 1 < ts.size() && ts[ptr + 1] - ts[ptr] <= temp - ts[ptr + 1]) {
            ++ptr;
        }
        ans = min(ans, temp - ts[ptr]);
    }
    cout << ans << "\n";
    return 0;
}