#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 600'000;
const int M = 26;
const int T = 2;
const ll MOD[T] = {1'000'000'007, 1'000'000'009};
const ll B[T] = {47, 47};
int n, a[N + 10];
int counter, last, len[N + 10], cnt[N + 10];
int lnk[N + 10], nxt[N + 10][M + 3];
pair<int, int> h[2][N + 10];
int pw[T][N + 10];
int pre[N + 10], mark[N + 10];
int fen[3][N + 10];
vector<int> st1[N + 10], en1[N + 10];
vector<int> st2[N + 10], en2[N + 10];
void readInput() {
string str;
cin >> str;
n = (int) str.size();
for (int i = 1; i <= n; i++)
a[i] = str[i - 1] - 'a';
}
void calcHash() {
for (int x = 0; x < 2; x++) {
h[x][0] = {0, 0};
for (int i = 1; i <= n; i++) {
h[x][i].first = ((ll) h[x][i - 1].first * B[0] + a[i]) % MOD[0];
h[x][i].second = ((ll) h[x][i - 1].second * B[1] + a[n - i + 1]) % MOD[1];
}
}
}
void calcPw() {
for (int t = 0; t < T; t++) {
pw[t][0] = 1;
for (int i = 1; i <= n; i++)
pw[t][i] = (ll) pw[t][i - 1] * B[t] % MOD[t];
}
}
pair<ll, ll> getHash(int t, int l, int r) {
ll res1 = ((ll) h[t][r].first - (ll) h[t][l - 1].first * pw[0][r - l + 1] % MOD[0] + MOD[0]) % MOD[0];
ll res2 = ((ll) h[t][r].second - (ll) h[t][l - 1].second * pw[1][r - l + 1] % MOD[1] + MOD[1]) % MOD[1];
return {res1, res2};
}
bool isPalindrome(int l, int r) {
pair<ll, ll> p1 = getHash(0, l, r);
pair<ll, ll> p2 = getHash(1, n - r + 1, n - l + 1);
//cout << l << ' ' << r << ":::::: " << (p1 == p2) << endl;
return p1 == p2;
}
int newVer(int v = 0) {
int u = ++counter;
if (v)
for (int j = 0; j < M; j++)
nxt[u][j] = nxt[v][j];
return u;
}
int calcFirstHave(int pnt, int newLast, int c) {
while (pnt && !nxt[pnt][c]) {
nxt[pnt][c] = newLast;
pnt = lnk[pnt];
}
return pnt;
}
void changeTillHave(int pnt, int c, int x, int y) {
while (pnt && nxt[pnt][c] == x) {
nxt[pnt][c] = y;
pnt = lnk[pnt];
}
}
void addChar(int c) {
int idx = calcFirstHave(last, newVer(), c);
len[counter] = len[last] + 1;
last = counter;
if (!idx || len[nxt[idx][c]] == len[idx] + 1)
lnk[last] = (idx? nxt[idx][c]: 1);
else {
int v = nxt[idx][c], u = newVer(nxt[idx][c]);
changeTillHave(idx, c, v, u);
lnk[u] = lnk[v];
len[u] = len[idx] + 1;
lnk[v] = lnk[last] = u;
}
}
void calcSuffixAuto() {
counter = 1;
last = 1;
for (int i = 1; i <= n; i++)
addChar(a[i]);
}
void calcCnt() {
for (int pnt = last; pnt != 1; pnt = lnk[pnt])
cnt[pnt] = 1;
vector<pair<int, int>> vec;
for (int i = 1; i <= counter; i++)
vec.push_back({len[i], i});
sort(vec.begin(), vec.end());
for (int i = counter - 1; i >= 0; i--) {
int u = vec[i].second;
for (int j = 0; j < M; j++)
cnt[u] += cnt[nxt[u][j]];
}
}
void calcPre() {
pre[0] = 1;
for (int i = 1; i <= n; i++)
pre[i] = nxt[pre[i - 1]][a[i]];
for (int i = 1; i <= n; i++)
if (!mark[pre[i]])
for (int j = pre[i]; j != 1 && !mark[j]; j = lnk[j])
mark[j] = i;
}
void update(int t, int idx, int val) {
for (; idx <= n; idx += idx & -idx)
fen[t][idx] += val;
}
int get(int t, int idx) {
int res = 0;
for (; idx; idx -= idx & -idx)
res += fen[t][idx];
return res;
}
int getFirst(int t, int low) {
int idx = 0, remain = get(t, low - 1);
for (int j = M; j >= 0; j--)
if (idx + (1 << j) <= n && fen[t][idx + (1 << j)] <= remain) {
idx += (1 << j);
remain -= fen[t][idx];
}
return idx + 1;
}
pair<int, int> calcSeg1(int i) {
int l = 0, r = min(i, n - i + 1);
while (r - l > 1) {
int mid = (l + r) >> 1;
if (isPalindrome(i - mid, i + mid))
l = mid;
else
r = mid;
}
return {i, i + l};
}
pair<int, int> calcSeg2(int i) {
int l = 1, r = min(i, n - i + 2);
while (r - l > 1) {
int mid = (l + r) >> 1;
if (isPalindrome(i - mid, i + mid - 1))
l = mid;
else
r = mid;
}
return {i, i + l - 1};
}
void calcStEn() {
for (int i = 1; i <= n; i++) {
//cout << "p1 " << endl;
pair<int, int> p1 = calcSeg1(i);
st1[p1.first].push_back(i);
en1[p1.second].push_back(i);
//cout << "p2" << endl;
if (1 < i && a[i] == a[i - 1]) {
pair<int, int> p2 = calcSeg2(i);
st2[p2.first].push_back(i);
en2[p2.second].push_back(i);
}
//cout << i << ": " << p1.first << ' ' << p1.second << endl;
}
for (int i = 1; i <= n; i++) {
st1[i].shrink_to_fit();
en1[i].shrink_to_fit();
st2[i].shrink_to_fit();
en2[i].shrink_to_fit();
}
}
ll check1(int l, int r, int u) {
int mid1 = (r + l + 1) / 2;
mid1 = getFirst(1, mid1);
if (mid1 <= r)
return (ll) (2 * (r - mid1) + 1) * (ll) cnt[u];
return 0;
}
ll check2(int l, int r, int u) {
if (l == r)
return 0;
int mid2 = (r + l + 2) / 2;
mid2 = getFirst(2, mid2);
if (mid2 <= r)
return (ll) (2 * (r - mid2 + 1)) * (ll) cnt[u];
return 0;
}
ll calcAns(int i) {
if (mark[pre[i]] != i)
return 0;
ll res = 0;
for (int u = pre[i]; u != 1 && mark[u] == i; u = lnk[u]) {
int r = i;
int l = i - len[u] + 1;
res = max(res, check1(l, r, u));
res = max(res, check2(l, r, u));
}
return res;
}
void calcAns() {
ll ans = 0;
for (int i = 1; i <= n; i++) {
for (auto idx: st1[i])
update(1, idx, 1);
for (auto idx: st2[i])
update(2, idx, 1);
ans = max(ans, calcAns(i));
for (auto idx: en1[i])
update(1, idx, -1);
for (auto idx: en2[i])
update(2, idx, -1);
}
cout << ans << flush;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
readInput();
calcHash();
calcPw();
calcSuffixAuto();
calcCnt();
calcPre();
calcStEn();
calcAns();
return 0;
}
