#include <bits/stdc++.h>
using namespace std;
#define int int64_t //be careful about this
#define endl "\n"
#define f(i,a,b) for(int i=int(a);i<int(b);++i)
#define pr pair
#define ar array
#define fr first
#define sc second
#define vt vector
#define pb push_back
#define eb emplace_back
#define SZ(x) ((int)(x).size())
#define all(a) (a).begin(),(a).end()
#define allr(a) (a).rbegin(),(a).rend()
#define mem(a,b) memset(a, b, sizeof(a))
template<class A> void rd(vt<A>& v);
template<class T> void rd(T& x){ cin >> x;}
template<class H, class... T> void rd(H& h, T&... t) { rd(h); rd(t...);}
template<class A> void rd(vt<A>& x) { for(auto& a : x) rd(a);}
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0;}
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0;}
template<typename T>
void __p(T a) {
cout<<a;
}
template<typename T, typename F>
void __p(pair<T, F> a) {
cout<<"{";
__p(a.first);
cout<<",";
__p(a.second);
cout<<"}\n";
}
template<typename T>
void __p(std::vector<T> a) {
cout<<"{";
for(auto it=a.begin(); it<a.end(); it++)
__p(*it),cout<<",}\n"[it+1==a.end()];
}
template<typename T, typename ...Arg>
void __p(T a1, Arg ...a) {
__p(a1);
__p(a...);
}
template<typename Arg1>
void __f(const char *name, Arg1 &&arg1) {
cout<<name<<" : ";
__p(arg1);
cout<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char *names, Arg1 &&arg1, Args &&... args) {
int bracket=0,i=0;
for(;; i++)
if(names[i]==','&&bracket==0)
break;
else if(names[i]=='(')
bracket++;
else if(names[i]==')')
bracket--;
const char *comma=names+i;
cout.write(names,comma-names)<<" : ";
__p(arg1);
cout<<" | ";
__f(comma+1,args...);
}
void setIO(string s = "") {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// remove this when size of input is not fixed.
cin.exceptions(cin.failbit);
cout.precision(15); cout << fixed;
if(SZ(s)){
freopen((s+".in").c_str(),"r",stdin);
freopen((s+".out").c_str(),"w",stdout);
}
}
/*********************************************Look Below******************************************************************/
/*
* description :- palindromic tree for a string which is genralized version of kmp for palindromes.
* indexing of palindromic tree starts from 1.
* source :- http://adilet.org/blog/palindromic-tree/.
* verification :- https://www.spoj.com/status/NUMOFPAL,deepkamal/
*/
template<int MAX_N,int ALPHABET>
struct palindromic_tree {
static const int INF = 1e9;
struct node {
// the next node which stores c + palindrome + c
array<int,ALPHABET> next;
// length of the current palindrome
int length;
// maximum proper suffix of the current palindrome which is also a palindrome.
int suffix_link;
// lazy value.
int lazy;
node(){
next.fill(-INF);
length = suffix_link = lazy = -INF;
}
};
// our string
string s;
// our palindromic tree
node tree[MAX_N];
// total number of nodes
int total_nodes;
// maximum suffix palindrome of present string.
int max_suffix;
palindromic_tree() {
// node 1 - root with length -1, node 2 - root with length 0
tree[1].length = -1, tree[1].suffix_link = 1, tree[1].lazy = 0;
tree[2].length = 0, tree[2].suffix_link = 1, tree[2].lazy = 0;
total_nodes = 2;
max_suffix = 2;
}
bool add_char(char _c) {
s.push_back(_c);
int pos = int(s.size()) - 1;
int cur_suffix = max_suffix, cur_length = 0;
int c = s[pos] - 'a';
while(true){
cur_length = tree[cur_suffix].length;
if(pos - 1 - cur_length >= 0 && s[pos - 1 - cur_length] == s[pos]){
break;
}
cur_suffix = tree[cur_suffix].suffix_link;
}
if(tree[cur_suffix].next[c] > 0){
max_suffix = tree[cur_suffix].next[c];
++tree[max_suffix].lazy;
return false;
}
int now = ++total_nodes;
max_suffix = now;
tree[now].length = tree[cur_suffix].length + 2;
tree[cur_suffix].next[c] = now;
tree[now].lazy = 1;
if(tree[now].length == 1){
tree[now].suffix_link = 2;
return true;
}
while(true){
cur_suffix = tree[cur_suffix].suffix_link;
cur_length = tree[cur_suffix].length;
if(pos - 1 - cur_length >= 0 && s[pos - 1 - cur_length] == s[pos]){
tree[now].suffix_link = tree[cur_suffix].next[c];
break;
}
}
return true;
}
void fun(){
int best = 0;
for(int i = total_nodes; i >= 1; --i){
int j = tree[i].suffix_link;
tree[j].lazy += tree[i].lazy;
ckmax(best,tree[i].length * tree[i].lazy);
}
cout << best;
return;
}
};
palindromic_tree<300077,26> pdt;
signed main(){
setIO();
string s; rd(s);
for(auto c : s) pdt.add_char(c);
pdt.fun();
}
