#include <vector>
#include <algorithm>
#include <iostream>
#include <set>
#include <cmath>
#include <map>
#include <random>
#include <cassert>
#include <ctime>
#include <cstdlib>
#include <queue>
#include <limits.h>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
using namespace std;
int64_t binPow (int64_t x, int64_t y, int64_t MOD) {
x %= MOD;
int64_t res = x;
int64_t ans = 1;
while (y > 0) {
if (y & 1) {
ans *= res, ans %= MOD;
}
res *= res, res %= MOD;
y /= 2;
}
return ans;
}
int64_t inv (int64_t x, int64_t MOD) {
return binPow(x, MOD - 2, MOD);
}
vector<int64_t> powr = {1};
vector<int64_t> ipowr = {1};
struct Hasher {
void resz (int mod, int base, string str) {
int n = str.size();
this->sz = n;
this->MOD = mod, this->BASE = base;
this->pref.assign(n + 1, 0);
for (int i = 1; i <= n; i++) {
pref[i] = (pref[i - 1] + (powr[n - i] * (str[i - 1] - 'a' + 1)) % MOD) % MOD;
pref[i] %= MOD;
}
}
int sz;
int MOD;
int BASE;
vector<int64_t> pref;
int64_t query (int l, int r) {
if (l > sz || r > sz || l > r || l < 0 || r < 0) return -1;
return (ipowr[sz - r - 1] * (pref[r + 1] - pref[l] + MOD) % MOD) % MOD;
}
};
Hasher h1;
Hasher h2;
string s1;
bool isPalindrome (int l, int r) {
if (l < 0 || r >= s1.length()) return false;
return (h1.query(l, r) == h2.query((int)s1.length() - r - 1, (int)s1.length() - l - 1));
}
vector<int> suffix_array(string S) {
int N = S.size();
vector<int> sa(N), classes(N);
for (int i = 0; i < N; i++) {
sa[i] = N - 1 - i;
classes[i] = S[i];
}
stable_sort(sa.begin(), sa.end(), [&S](int i, int j) {
return S[i] < S[j];
});
for (int len = 1; len < N; len *= 2) {
vector<int> c(classes);
for (int i = 0; i < N; i++) {
bool same = i && sa[i - 1] + len < N
&& c[sa[i]] == c[sa[i - 1]]
&& c[sa[i] + len / 2] == c[sa[i - 1] + len / 2];
classes[sa[i]] = same ? classes[sa[i - 1]] : i;
}
vector<int> cnt(N), s(sa);
for (int i = 0; i < N; i++)
cnt[i] = i;
for (int i = 0; i < N; i++) {
int s1 = s[i] - len;
if (s1 >= 0)
sa[cnt[classes[s1]]++] = s1;
}
}
return sa;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
while (powr.size() != 1e6 + 5) {
powr.push_back(powr.back() * 31);
powr.back() %= (int)1e9 + 9;
}
ipowr.resize(powr.size());
ipowr[0] = 1; ipowr[1] = inv(powr[1], 1e9 + 9);
for (int i = 2; i < powr.size(); i++) {
ipowr[i] = (ipowr[i - 1] * ipowr[1]) % ((int)1e9 + 9);
}
cin >> s1;
h1.resz((int)1e9 + 9, 31, s1);
reverse(s1.begin(), s1.end());
h2.resz((int)1e9 + 9, 31, s1);
reverse(s1.begin(), s1.end());
vector<pair<int,int>> vec;
for (int i = 0; i < s1.size(); i++) {
int l = 0;
int r = s1.length();
while (l != r) {
//cout << l << " " << r << '\n';
int m = (l + r + 1)/2;
if (isPalindrome(i - m, i + m)) {
l = m;
} else {
r = m - 1;
}
}
vec.emplace_back(i - l, i + l);
//[...aa...]
if (i == s1.length() || s1[i] != s1[i + 1]) {
continue;
}
l = 0;
r = s1.length();
while (l != r) {
int m = (l + r + 1)/2;
if (isPalindrome(i - m, i + m + 1)) {
l = m;
} else {
r = m - 1;
}
}
vec.emplace_back(i - l, i + l + 1);
//cout << i << " " << l << '\n';
}
map<int64_t,pair<int,int>> myMap;
for (auto& p: vec) {
pair<int,int> q = p;
while (q.first <= q.second) {
if (myMap.count(h1.query(q.first, q.second))) {
break;
}
myMap[h1.query(q.first, q.second)] = q;
q.first++, q.second--;
}
}
vector<int> v = suffix_array(s1);
vector<int> id(v.size() + 1);
for (int i = 0; i < v.size(); i++) {
id[v[i]] = i;
}
int64_t ans = 0;
for (auto& p: myMap) {
int tot = h1.query(p.second.first, p.second.second);
int l = 0;
int r = id[p.second.first];
while (l != r) {
int m = (l + r)/2;
if (h1.query(v[m], v[m] + p.second.second - p.second.first) == tot) {
r = m;
} else {
l = m + 1;
}
}
int L = l;
l = id[p.second.first];
r = s1.length() - 1;
while (l != r) {
int m = (l + r + 1)/2;
if (h1.query(v[m], v[m] + p.second.second - p.second.first) == tot) {
l = m;
} else {
r = m - 1;
}
}
if (p.second.first - p.second.second == 2 && l - L + 1 == 10) {
cout << p.second.first << " " << p.second.second << " " << l - L + 1 << '\n';
}
ans = max(ans, (int64_t)(p.second.second - p.second.first + 1) * (l - L + 1));
}
cout << ans;
}
