#include #include typedef long long int ll; using namespace std; typedef pair P; using namespace atcoder; template using min_priority_queue = priority_queue, greater>; #define USE998244353 #ifdef USE998244353 const ll MOD = 998244353; using mint = modint998244353; #else const ll MOD = 1000000007; using mint = modint1000000007; #endif const int MAX = 2000005; long long fac[MAX], finv[MAX], inv[MAX]; void COMinit() { fac[0] = fac[1] = 1; finv[0] = finv[1] = 1; inv[1] = 1; for (int i = 2; i < MAX; i++){ fac[i] = fac[i - 1] * i % MOD; inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD; finv[i] = finv[i - 1] * inv[i] % MOD; } } long long COM(int n, int k){ if (n < k) return 0; if (n < 0 || k < 0) return 0; return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD; } ll gcd(ll x, ll y) { if (y == 0) return x; else if (y > x) { return gcd (y, x); } else return gcd(x % y, y); } ll lcm(ll x, ll y) { return x / gcd(x, y) * y; } ll my_sqrt(ll x) { // ll m = 0; ll M = 3000000001; while (M - m > 1) { ll now = (M + m) / 2; if (now * now <= x) { m = now; } else { M = now; } } return m; } ll keta(ll num, ll arity) { ll ret = 0; while (num) { num /= arity; ret++; } return ret; } ll ceil(ll n, ll m) { // n > 0, m > 0 ll ret = n / m; if (n % m) ret++; return ret; } ll pow_ll(ll x, ll n) { if (n == 0) return 1; if (n % 2) { return pow_ll(x, n - 1) * x; } else { ll tmp = pow_ll(x, n / 2); return tmp * tmp; } } vector compress(vector& v) { // [3 5 5 6 1 1 10 1] -> [1 2 2 3 0 0 4 0] vector u = v; sort(u.begin(), u.end()); u.erase(unique(u.begin(),u.end()),u.end()); map mp; for (int i = 0; i < u.size(); i++) { mp[u[i]] = i; } for (int i = 0; i < v.size(); i++) { v[i] = mp[v[i]]; } return v; } int main() { string s; cin >> s; const int N = s.length(); vector> isPalindrome(N, vector(N, false)); for (int mid = 0; mid < N; mid++) { int left = mid; int right = mid; while ((left >= 0) && (right < N) && (s[left] == s[right])) { isPalindrome[left][right] = true; left--; right++; } } for (int midLeft = 0; midLeft < N; midLeft++) { int left = midLeft; int right = midLeft + 1; while ((left >= 0) && (right < N) && (s[left] == s[right])) { isPalindrome[left][right] = true; left--; right++; } } vector minLen(N, 0); // try to maximize for (int i = 0; i < N; i++) { if (isPalindrome[0][i]) { minLen[i] = i + 1; continue; } // minLen[i] ans of [s[0]...s[i]] for (int j = 0; j < i; j++) { // split s[0]...s[j] s[j + 1]...s[i] if (isPalindrome[j + 1][i]) { int cand = min((i - j), minLen[j]); minLen[i] = max(cand, minLen[i]); } } } cout << minLen[N - 1] << endl; return 0; }