#include <bits/stdc++.h>
using namespace std;
#define POPCOUNT(n) (__builtin_popcountll((n)))
#define CLZ(n) (__builtin_clzll((n)))
#define CTZ(n) (__builtin_ctzll((n)))
#define LOG(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))
#define Int __int128
#define fi first
#define se second
#define hash pvhdeptrai
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;
template <class T1, class T2> bool maximize(T1 &x, T2 y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <class T1, class T2> bool minimize(T1 &x, T2 y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <class T> void remove_duplicate(vector<T> &ve) {
sort (ve.begin(), ve.end());
ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
template <class T1, class T2> T1 random(T1 l, T2 r) {
return uniform_int_distribution<T1>(l, r)(rng);
}
template <class T> T random(T r) {
return rng() % r;
}
const int N = 6e5 + 5, LG = 20;
const int MOD = 1e9 + 9;
const int inf = 1e9;
const long long INF = 1e18;
const int base = 311;
string s;
int le[N], ri[N], pw[N];
int hash[N], rev_hash[N];
int rmq[N][LG];
struct SuffixArray {
vector<int> sa, lcp, rank, w;
vii pa;
string str;
int n;
SuffixArray(string _s = "") {
str = _s, n = str.size();
sa.assign(n, 0), lcp.assign(n, 0), rank.assign(n, 0), w.assign(n, 0);
pa.assign(n, make_pair(0, 0));
get_sa(), get_lcp();
}
void get_sa() {
for (int i = 0; i < n; ++i) {
sa[i] = i;
pa[i] = make_pair(int(str[i]), 0);
}
auto cmp = [&](int x, int y) {
return pa[x] < pa[y];
};
sort (sa.begin(), sa.end(), cmp);
for (int len = 1; len <= n; len <<= 1) {
int cnt = 0;
for (int i = 0; i < n; ++i) {
if (i > 0 && pa[sa[i - 1]] == pa[sa[i]]) w[sa[i]] = w[sa[i - 1]];
else w[sa[i]] = ++cnt;
}
if (cnt == n) break;
for (int i = 0; i < n; ++i) {
pa[i] = make_pair(w[i], (i + len < n ? w[i + len] : 0));
}
sort (sa.begin(), sa.end(), cmp);
}
}
void get_lcp() {
for (int i = 0; i < n; ++i) rank[sa[i]] = i;
for (int i = 0, k = 0; i < n; lcp[rank[i++]] = k) {
if (rank[i] > 0) {
int j = sa[rank[i] - 1];
if (k > 0) --k;
while (str[i + k] == str[j + k]) ++k;
}
else k = 0;
}
}
};
int getHash(int l, int r) {
return (0ll + hash[r] - 1ll * hash[l - 1] * pw[r - l + 1] + 1ll * MOD * MOD) % MOD;
}
int get_revHash(int l, int r) {
return (0ll + rev_hash[l] - 1ll * rev_hash[r + 1] * pw[r - l + 1] + 1ll * MOD * MOD) % MOD;
}
bool isPalin(int l, int r) {
return getHash(l, r) == get_revHash(l, r);
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> s;
string t(1, '#');
for (int i = 0; i < s.size(); ++i) {
t += s[i];
t += '#';
}
// cerr << "t = " << t << '\n';
int n = t.size(); SuffixArray T(t);
if (s.size() > 150000) assert(false);
for (int i = 0; i < n; ++i) rmq[i][0] = T.lcp[i];
for (int i = 1; i < LG; ++i) for (int j = 0; j + MASK(i) - 1 < n; ++j) {
rmq[j][i] = min(rmq[j][i - 1], rmq[j + MASK(i - 1)][i - 1]);
}
auto get_lcp = [&](int l, int r) {
++l; int g = LOG(r - l + 1);
return min(rmq[l][g], rmq[r - MASK(g) + 1][g]);
};
pw[0] = 1;
for (int i = 1; i <= n; ++i) pw[i] = 1ll * pw[i - 1] * base % MOD;
hash[0] = t[0];
for (int i = 1; i < n; ++i)
hash[i] = (1ll * hash[i - 1] * base + t[i]) % MOD;
for (int i = n - 1; i >= 0; --i)
rev_hash[i] = (1ll * rev_hash[i + 1] * base + t[i]) % MOD;
ll ans = 0;
for (int i = 0; i < n; ++i) {
for (int len = max(0, T.lcp[T.rank[i]] - 1); ; ++len) {
if (i - len < 0 || i + len >= n) break;
if (!isPalin(i - len, i + len)) break;
int real_len = 2 * len + 1;
if (t[i] == '#') {
int x = (len / 2);
real_len -= 2 * x + 1;
}
else {
int x = (len + 1) / 2;
real_len -= 2 * x;
}
int p = T.rank[i - len];
int low = 0, high = p - 1, L = p, R = p;
while (low <= high) {
int mid = (low + high) >> 1;
if (get_lcp(mid, p) >= 2 * len + 1) high = (L = mid) - 1;
else low = mid + 1;
}
low = p + 1, high = n - 1;
while (low <= high) {
int mid = (low + high) >> 1;
if (get_lcp(p, mid) >= 2 * len + 1) low = (R = mid) + 1;
else high = mid - 1;
}
maximize(ans, 1ll * real_len * (R - L + 1));
}
}
cout << ans;
return 0;
}
