#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define ld long double
#define ll long long
mt19937 rnd(51);
const int INF = 1e9, MOD1 = 1e9 + 7, p1 = 31, MOD2 = 1e9 + 33, p2 = 37;
bool is_palindrome(string s) {
return s == (string){s.rbegin(), s.rend()};
}
int solve1(string s) {
int n = s.size(), ans = -INF;
map<string, int> cnt;
for (int i = 0; i < n; i++) {
for (int j = 1; j + i <= n; j++) {
cnt[s.substr(i, j)]++;
}
}
for (int i = 0; i < n; i++) {
for (int j = n - i; j >= 1; j--) {
if (is_palindrome(s.substr(i, j))) {
ans = max(ans, cnt[s.substr(i, j)] * j);
}
}
}
return ans;
}
struct Hash {
ll MOD, p;
vector<ll> po, h;
Hash(string s, ll MOD_, ll p_) {
MOD = MOD_, p = p_;
int n = s.size();
po.resize(n + 1);
h.resize(n + 1);
po[0] = 1;
for (int i = 1; i <= n; i++) {
po[i] = (po[i - 1] * p) % MOD;
}
for (int i = 0; i < n; i++) {
h[i + 1] = (h[i] * p + s[i] - 'a' + 1) % MOD;
}
}
int get(int l, int r) {
r++;
return (((h[r] - h[l] * po[r - l]) % MOD) + MOD) % MOD;
}
};
struct SegTree {
vector<int> t;
SegTree(int n) {
t.resize(4 * n, -1);
}
void update(int v, int tl, int tr, int l, int r, int val) {
if (l > r) return;
if (tl == l && tr == r) {
t[v] = max(t[v], val);
return;
}
int tm = (tl + tr) / 2;
update(2 * v, tl, tm, l, min(r, tm), val), update(2 * v + 1, tm + 1, tr, max(l, tm + 1), r, val);
}
int get(int v, int l, int r, int pos) {
if (l == r) {
return t[v];
}
int m = (l + r) / 2;
if (pos <= m) {
return max(t[v], get(2 * v, l, m, pos));
} else {
return max(t[v], get(2 * v + 1, m + 1, r, pos));
}
}
};
int solve2(string s) {
int n = s.size(), ans = -INF;
map<int, int> cnt;
Hash h(s, MOD1, p1), hrev((string){s.rbegin(), s.rend()}, MOD1, p1);
for (int i = 0; i < n; i++) {
for (int j = 1; j + i <= n; j++) {
cnt[h.get(i, i + j - 1)]++;
}
}
SegTree odd(n), even(n);
for (int i = 0; i < n; i++) {
int l = 0, r = n;
while (r - l > 1) {
int mid = (r + l) / 2;
if (i - mid >= 0 && i + mid < n && h.get(i - mid, i + mid) == hrev.get(n - i - mid - 1, n - i + mid - 1)) {
l = mid;
} else {
r = mid;
}
}
odd.update(1, 0, n - 1, i - l, i, i);
if (i + 1 < n && s[i] == s[i + 1]) {
int l = 0, r = n;
while (r - l > 1) {
int mid = (r + l) / 2;
if (i - mid >= 0 && i + mid + 1 < n && h.get(i - mid, i + mid + 1) == hrev.get(n - i - mid - 2, n - i + mid - 1)) {
l = mid;
} else {
r = mid;
}
}
even.update(1, 0, n - 1, i - l, i, i);
}
}
for (int i = 0; i < n; i++) {
int j = odd.get(1, 0, n - 1, i), k = even.get(1, 0, n - 1, i), pos = -1;
if (j != -1) {
pos = max(pos, i + 2 * (j - i));
}
if (k != -1) {
pos = max(pos, i + 1 + 2 * (k - i));
}
if (pos != -1) {
ans = max(ans, cnt[h.get(i, pos)] * (pos - i + 1));
}
}
return ans;
}
signed main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif // LCOAL
ios_base::sync_with_stdio(0);
cin.tie(0);
while (0) {
int n = rnd() % 10 + 1;
string s = "";
for (int i = 0; i < n; i++) {
s += rnd() % 5 + 'a';
}
auto res1 = solve1(s), res2 = solve2(s);
if (res1 != res2) {
cout << s << endl << res1 << ' ' << res2 << endl;
return 0;
}
cout << "ok" << endl;
}
string s;
cin >> s;
cout << solve2(s) << endl;
return 0;
}
