#include <bits/stdc++.h>
using namespace std;
constexpr int MOD1 = (int) 1e9 + 7;
constexpr int MOD2 = (int) 1e9 + 9;
struct Hash {
int val1 = 0, val2 = 0;
Hash operator*(pair<int, int> x) const {
Hash h;
h.val1 = (1LL * val1 * x.first) % MOD1;
h.val2 = (1LL * val2 * x.second) % MOD2;
return h;
}
Hash operator*(const Hash& rhs) const {
Hash h;
h.val1 = (1LL * val1 * rhs.val1) % MOD1;
h.val2 = (1LL * val2 * rhs.val2) % MOD2;
return h;
}
Hash operator-(const Hash& rhs) const {
Hash h;
h.val1 = (val1 - rhs.val1 + MOD1);
if (h.val1 >= MOD1)
h.val1 -= MOD1;
h.val2 = (val2 - rhs.val2 + MOD2);
if (h.val2 >= MOD2)
h.val2 -= MOD2;
return h;
}
Hash operator+(int x) const {
Hash h;
h.val1 = val1 + x;
if (h.val1 >= MOD1)
h.val1 -= MOD1;
h.val2 = val2 + x;
if (h.val2 >= MOD2)
h.val2 -= MOD2;
return h;
}
Hash& operator=(int x) {
val1 = val2 = x;
return *this;
}
bool operator==(const Hash& rhs) const {
return val1 == rhs.val1 && val2 == rhs.val2;
}
};
namespace std {
template<>
struct hash<Hash> {
size_t operator()(const Hash& h) const noexcept {
return h.val1 ^ h.val2;
}
};
}
using ull = Hash;
constexpr pair<int, int> BASE = {77557187, 2269733};
constexpr int MAXN = (int) 3e5;
char s[MAXN + 5];
ull pref_hash[MAXN + 5];
ull power[MAXN + 5];
inline ull Get(int l, int r) {
return pref_hash[r] - pref_hash[l - 1] * power[r - l + 1];
}
char str[2 * MAXN + 5];
int len[2 * MAXN + 5];
int Build(char* s, int n) {
power[0] = 1;
for (int i = 1; i <= n; i++) {
pref_hash[i] = pref_hash[i - 1] * BASE + (s[i] - 'a' + 1);
power[i] = power[i - 1] * BASE;
}
int size = 0;
str[++size] = '*';
for (int i = 1; i <= n; i++) {
str[++size] = s[i];
str[++size] = '*';
}
return size;
}
void Manacher(char* str, int size) {
int pos = 1;
len[1] = 1;
for (int i = 2; i <= size; i++) {
len[i] = 1;
if (pos + len[pos] >= i) {
len[i] = min(pos + len[pos] - i, len[2 * pos - i]);
}
while (i - len[i] >= 1 && i + len[i] <= size && str[i - len[i]] == str[i + len[i]]) {
len[i]++;
}
if (pos + len[pos] < i + len[i]) {
pos = i;
}
}
}
unordered_map<ull, int> nodeId;
vector<vector<int>> g;
vector<int> nodeFreq(1);
vector<int> nodeLen(1);
void BuildGraph(int size) {
int ID = 0;
for (int i = 1; i <= size; i++) {
int l = len[i];
if (i % 2 == l % 2) {
l--;
}
int prevId = 0;
while (l > 0) {
ull currHash;
int mid = i / 2;
if (i % 2 == 1) {
currHash = Get(mid - l / 2 + 1, mid + l / 2);
} else {
currHash = Get(mid - l / 2, mid + l / 2);
}
int& currId = nodeId[currHash];
if (currId == 0) {
currId = ++ID;
nodeLen.push_back(l);
nodeFreq.push_back(0);
}
if (currId >= (int)g.size()) {
g.resize(currId + 1);
}
if (prevId == 0) {
nodeFreq[currId]++;
} else {
g[prevId].push_back(currId);
}
if (currId != ID) {
break;
}
prevId = currId;
l -= 2;
}
}
}
int main() {
#ifdef HOME
ifstream cin("input.in");
ofstream cout("output.out");
#endif
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> (s + 1);
int n = strlen(s + 1);
int size = Build(s, n);
Manacher(str, size);
// for (int i = 1; i <= size; i++) {
// cerr << (char)str[i] << " ";
// }
// cerr << "\n";
// for (int i = 1; i <= size; i++) {
// cerr << len[i] << " ";
// }
// cerr << "\n";
BuildGraph(size);
int nodes = (int)g.size() - 1;
vector<int> order(nodes);
iota(order.begin(), order.end(), 1);
sort(order.begin(), order.end(), [](const int& a, const int& b) {
return nodeLen[a] > nodeLen[b];
});
long long answer = 0;
for (auto node : order) {
// cerr << nodeFreq[node] << " " << nodeLen[node] << "\n";
answer = max(answer, 1LL * nodeFreq[node] * nodeLen[node]);
for (auto son : g[node]) {
nodeFreq[son] += nodeFreq[node];
}
}
cout << answer;
return 0;
}
