#include<bits/stdc++.h>
using namespace std;
using int64 = int64_t;
#define FOR(i, l, r) for(int i = (l), _r = (r); i <= _r; ++i)
#define FORD(i, r, l) for(int i = (r), _l = (l); i >= _l; --i)
#define rep(i, l, r) for(int i = (l), _r = (r); i < _r; ++i)
#define repd(i, r, l) for(int i = (r) - 1, _l = l; i >= _l; --i)
#define left __left
#define right __right
#define next __next
#define prev __prev
#define div __div
#define pb push_back
#define pf push_front
#define all(v) v.begin(), v.end()
#define sz(v) (int)v.size()
#define compact(v) v.erase(unique(all(v)), end(v))
#define dbg(v) "[" #v " = " << (v) << "]"
#define file(name) if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
template<typename T>
bool minimize(T& a, const T& b){
if(a > b) return a = b, true;
return false;
}
template<typename T>
bool maximize(T& a, const T& b){
if(a < b) return a = b, true;
return false;
}
template<int dimension, typename T>
struct vec : public vector<vec<dimension - 1, T>> {
static_assert(dimension > 0, "Dimension must be positive !\n");
template<typename... Args>
vec(int n = 0, Args... args) : vector<vec<dimension - 1, T>> (n, vec<dimension - 1, T>(args...)) {}
};
template<typename T>
struct vec<1, T> : public vector<T> {
vec(int n = 0, T val = T()) : vector<T>(n, val) {}
};
void preprocess();
void init();
void process();
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
file("antuvu");
preprocess();
int T = 1; //cin >> T;
while(T--){
init();
process();
}
return 0;
}
// Palindrome Tree {{{
// Notes:
// - number of *distinct* palindrome substring <= N
// Tested:
// - https://oj.vnoi.info/problem/icpc22_mn_d
template<int MAXC = 26>
struct PalindromicTree {
PalindromicTree(const string& str)
: _sz(str.size() + 5),
next(_sz, vector<int> (MAXC, 0)),
link(_sz, 0), qlink(_sz, 0),
cnt(_sz, 0), right_id(_sz, 0),
len(_sz, 0), s(_sz, 0) {
init();
for (int i = 0; i < (int) str.size(); ++i) {
add(str[i], i);
}
count();
}
int _sz;
// returns vector of (left, right, frequency)
vector<tuple<int,int,int>> get_palindromes() {
vector<tuple<int,int,int>> res;
dfs(0, res);
dfs(1, res);
return res;
}
void dfs(int u, vector<tuple<int,int,int>>& res) {
if (u > 1) { // u = 0 and u = 1 are two empty nodes
res.emplace_back(right_id[u] - len[u] + 1, right_id[u], cnt[u]);
}
for (int i = 0; i < MAXC; ++i) {
if (next[u][i]) dfs(next[u][i], res);
}
}
int last, n, p;
vector<vector<int>> next, dlink;
vector<int> link, qlink, cnt, right_id, len, s;
int newnode(int l, int right) {
len[p] = l;
right_id[p] = right;
return p++;
}
void init() {
p = 0;
newnode(0, -1), newnode(-1, -1);
n = last = 0;
s[n] = -1, link[0] = 1;
}
int getlink(int x) {
while (s[n - len[x] - 1] != s[n]) {
if (s[n - len[link[x]] - 1] == s[n]) x = link[x];
else x = qlink[x];
}
return x;
}
void add(char c, int right) {
c -= 'a';
s[++n] = c;
int cur = getlink(last);
if (!next[cur][(int) c]) {
int now = newnode(len[cur] + 2, right);
link[now] = next[getlink(link[cur])][(int) c];
next[cur][(int) c] = now;
if (s[n - len[link[now]]] == s[n - len[link[link[now]]]]) {
qlink[now] = qlink[link[now]];
}
else {
qlink[now] = link[link[now]];
}
}
last = next[cur][(int) c];
cnt[last]++;
}
void count() {
for (int i = p - 1; i >= 0; i--) {
cnt[link[i]] += cnt[i];
}
}
};
// }}}
void preprocess(){
}
void init(){
}
void process(){
string s;
cin >> s;
PalindromicTree<26> T(s);
vector<tuple<int, int, int>> p = T.get_palindromes();
long long ans = 0;
for(int i = 0; i < sz(p); ++i){
int l, r, cnt;
tie(l, r, cnt) = p[i];
maximize(ans, 1ll * cnt * (r - l + 1));
}
cout << ans << '\n';
}
