#include<iostream>
#include<vector>
using namespace std;
using ll = long long;
#define forn(i, n) for(int i=0; i<(int)n; ++i)
#define forsn(i, s, n) for(int i=s; i<(int)n; ++i)
#define dforn(i, n) for(int i=n-1; i>=0; --i)
#define PB push_back
struct trie{
int cnt=0, total=0, pos;
int up[20], nxt[28]={0};
trie(int Pos) : pos(Pos) {}
};
const int MAXN=600015;
int n, l=1, r=1, len[MAXN];
ll ans;
trie *root, *pal[MAXN];
string str, aux;
vector<trie*> bol;
void dfs(trie* v, int d, bool yes){
v->total=v->cnt;
forn(i, 28) if(v->nxt[i]){
dfs(bol[v->nxt[i]], d+1, yes^1);
v->total+=bol[v->nxt[i]]->total;
}
if(yes) ans=max(ans, ((ll)d)*v->total);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> aux;
str.resize(2*aux.size() + 1);
str[0]='$';
forn(i, aux.size()) str[2*i+1]=aux[i];
forn(i, aux.size()-1) str[2*i + 2]='z'+1;
str.back()='^';
n = str.size();
root = new trie(0);
bol.PB(root);
forn(i, 20) root->up[i]=0;
forsn(i, 1, n-1){
trie* cur=NULL;
if(i>=r) cur=root;
else{
len[i]=min(r-i, len[l+r-i]);
cur=pal[l+r-i];
int goUp=len[l+r-i]-len[i];
dforn(j, 20) if(goUp>=(1<<j)) goUp-=(1<<j), cur=bol[cur->up[j]];
}
while(str[i+len[i]]==str[i-len[i]]){
int pos=str[i+len[i]]-'a';
++len[i];
if(cur->nxt[pos]==0){
cur->nxt[pos]=bol.size();
bol.PB(new trie(bol.size()));
int* ptr=bol[cur->nxt[pos]]->up;
ptr[0]=cur->pos;
forn(j, 19) ptr[j+1]=bol[ptr[j]]->up[j];
}
cur=bol[cur->nxt[pos]];
}
if(i+len[i]>r) r=i+len[i], l=i-len[i];
pal[i]=cur;
cur->cnt++;
}
forn(i, 26) if(root->nxt[i]) dfs(bol[root->nxt[i]], 1, true);
if(root->nxt[26]) dfs(bol[root->nxt[26]], 1, false);
cout << ans << '\n';
}
