#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif
#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "["; REP(i, v.size()) out << v[i] << ", "; out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}
const int K = 26;
struct node{
array<int, K> next;
int len;
int fail;
int lazy = 0;
node(){
fill(all(next), -1);
}
};
struct paltree{
vector<node> tree;
string s;
int max_suffix_palindrome;
paltree(string _s) : s(_s){
tree.resize(2);
tree[0].len = -1; tree[0].fail = 0;
tree[1].len = 0; tree[1].fail = 0;
max_suffix_palindrome = 1;
}
void addletter(int pos){
int curr = max_suffix_palindrome;
int currlen = 0;
while(true){
currlen = tree[curr].len;
if(pos - 1 - currlen >= 0 && s[pos - 1 - currlen] == s[pos])
break;
curr = tree[curr].fail;
}
if(tree[curr].next[s[pos] - 'a'] != -1){
max_suffix_palindrome = tree[curr].next[s[pos] - 'a'];
tree[max_suffix_palindrome].lazy++;
return;
}
tree.push_back(node());
tree.back().len = tree[curr].len + 2;
tree[curr].next[s[pos] - 'a'] = (int)tree.size() - 1;
int nw = (int)tree.size() - 1;
max_suffix_palindrome = nw;
tree[max_suffix_palindrome].lazy++;
if(tree[nw].len == 1){
tree[nw].fail = 1;
return;
}
while(true){
curr = tree[curr].fail;
currlen = tree[curr].len;
if(pos - 1 - currlen >= 0 && s[pos - 1 - currlen] == s[pos]){
tree[nw].fail = tree[curr].next[s[pos] - 'a'];
break;
}
}
}
void construct_paltree(){
REP(i, s.length()){
addletter(i);
}
}
void propagate_lazy(){
vi dist(tree.size(), -1);
queue<int> q;
q.push(0);
q.push(1);
dist[0] = dist[1] = 0;
stack<int> st;
st.push(0); st.push(1);
while(!q.empty()){
int v = q.front();
q.pop();
REP(i, K){
if(tree[v].next[i] != -1){
if(dist[tree[v].next[i]] == -1){
q.push(tree[v].next[i]);
dist[tree[v].next[i]] = dist[v] + 1;
st.push(tree[v].next[i]);
}
}
}
}
while(!st.empty()){
int v = st.top();
st.pop();
tree[tree[v].fail].lazy += tree[v].lazy;
}
}
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
string s; cin >> s;
paltree P(s);
P.construct_paltree();
P.propagate_lazy();
ll ans = 0;
REP(j, P.tree.size()){
ans = max(ans, (ll)P.tree[j].len * P.tree[j].lazy);
}
cout << ans << "\n";
return 0;
}
