#include <iostream>
#include <map>
using namespace std;
#define int __int128
const int N = 3<<17;
int ph[N], sh[N], pw[N], mod = 100'000'000'000'000'037, Ans;
map<int, int> cnt[N], prv;
int get1(int l, int r){
return (ph[r] - ph[--l] * pw[r - l] % mod + mod) % mod;
}
int get2(int l, int r){
return (sh[l] - sh[++r] * pw[r - l] % mod + mod) % mod;
}
signed main(){
string s;
cin>>s;
int n = s.size();
for (int i=1;i<=n;i++)
ph[i] = (ph[i-1] * 99991 + s[i-1]) % mod;
for (int i=n;i>=1;i--)
sh[i] = (sh[i+1] * 99991 + s[i-1]) % mod;
for (int i=pw[0]=1;i<=n;i++)
pw[i] = pw[i-1] * 99991 % mod;
for (int i=1;i<=n;i++){
int l = 0, r = min(i, n - i + 1) + 1, h, hh;
while (l + 1 < r){
int mid = (l + r) / 2;
if (get1(i - mid + 1, i) == get2(i, i + mid - 1))
l = mid;
else
r = mid;
}
/////////////////////////////////////////////////
h = get1(i - l + 1, i);
cnt[l + l - 1][h]++;
while (l >= 1 and prv.find(h) == prv.end()){
l--;
hh = get1(i - l + 1, i);
prv[h] = hh, h = hh;
}
/////////////////////////////////////////////////
l = 0, r = min(i - 1, n - i + 1) + 1;
while (l + 1 < r){
int mid = (l + r) / 2;
if (get1(i - mid, i-1) == get2(i, i + mid - 1))
l = mid;
else
r = mid;
}
/////////////////////////////////////////////////
h = get1(i - l, i - 1);
cnt[l + l][h]++;
while (l >= 1 and prv.find(h) == prv.end()){
l--;
hh = get1(i - l, i - 1);
prv[h] = hh, h = hh;
}
/////////////////////////////////////////////////
}
for (int i=n;i>=1;i--){
for (auto [j, k] : cnt[i]){
Ans = max(Ans, i * k);
if (i - 2 > 0)
cnt[i - 2][prv[j]] += k;
}
}
cout<<(long long)Ans<<'\n';
}
