#include <bits/stdc++.h>
using namespace std;
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr)
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define REP(n) FOR(O, 1, (n))
#define f first
#define s second
#define pb push_back
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MAXN = 300100;
//const ll MOD1 = 1e9+7;
//const ll MOD2 = rng() % ((ll)1e7) + ((ll)1e8);
ll pwr (ll a, ll p, ll m) {
if (p == 0) return 1ll;
if (p == 1) return a%m;
ll ret = pwr(a, p/2, m);
ret = (ret*ret) % m;
if (p % 2 == 1) ret *= a%m;
return ret%m;
}
ll modInv (ll a, ll m) {
return pwr(a%m, m-2, m);
}
struct stringHash {
ll pw[MAXN];
ll pwInv[MAXN];
ll MOD;
ll pref[MAXN];
ll suf[MAXN];
int n;
void build (ll _MOD, string s, int _n) {
MOD = _MOD;
n = _n;
pw[0] = 1;
FOR(i, 1, n+1) pw[i] = (pw[i-1] * 26) % MOD;
FOR(i, 0, n+1) pwInv[i] = modInv(pw[i], MOD);
pref[0] = 0;
FOR(i, 1, n) {
pref[i] = (pref[i-1] * 26) % MOD;
pref[i] = (pref[i] + (s[i-1]-'a')) % MOD;
}
suf[n+1] = 0;
for (int i = n; i > 0; i--) {
suf[i] = (suf[i+1] * 26) % MOD;
suf[i] = (suf[i] + (s[i-1]-'a')) % MOD;
}
}
ll prefHsh (int i, int j) {
ll ret = pref[j] - ((pw[j-i+1] * pref[i-1])%MOD) + MOD;
ret %= MOD;
//ret = (ret * pwInv[j-1]) % MOD;
//ret = (ret * pw[n-i]) % MOD;
return ret;
}
ll sufHsh (int i, int j) {
ll ret = suf[i] - ((pw[j-i+1] * suf[j+1])%MOD) + MOD;
ret %= MOD;
//cout << " suf m = " << MOD << " i = " << i << " j = " << j << " 676 / 26*26 = " << ((676) * pwInv[2])%MOD << endl;
//cout << " suf[i] = " << suf[i] << " ret = " << ret << endl;
//ret = (ret * pwInv[n-i]) % MOD;
//ret = (ret * pw[j-1]) % MOD;
return ret;
}
bool pal (int i, int j) {
return prefHsh(i, j) == sufHsh(i, j);
}
};
int n;
string s;
stringHash h1, h2;
map<pair<ll, ll>, ll> cnt;
vector<pair<int, pair<ll,ll>>> srt;
map<pair<ll, ll>, pair<ll, ll>> shorten;
set<pair<ll, ll>> done;
void proc (int fr, int to) {
ll hsh1 = h1.prefHsh(fr, to);
ll hsh2 = h2.prefHsh(fr, to);
cnt[{hsh1, hsh2}]++;
while (true){
hsh1 = h1.prefHsh(fr, to);
hsh2 = h2.prefHsh(fr, to);
if (done.count({hsh1, hsh2})) return;
//cout << " fr = " << fr << " to = " << to << " hsh1 = " << hsh1 << " hsh2 = " << hsh2 << endl;
done.insert({hsh1, hsh2});
//toLen({hsh1, hsh2}) = to-fr+1;
srt.pb({to-fr+1, {hsh1, hsh2}});
fr += 1;
to -= 1;
if (fr > to) return;
ll h11 = h1.prefHsh(fr, to);
ll h22 = h2.prefHsh(fr, to);
shorten[{hsh1, hsh2}] = {h11, h22};
//cout << " shorten to h11 = " << h11 << " h22 = " << h22 << endl;
}
}
int main()
{
FAST_IO;
ll m1 = 1e9+7;
ll m2 = rng() % ((ll)1e7) + ((ll)1e8);
cin >> s;
n = s.length();
h1.build (m1, s, n);
h2.build (m2, s, n);
FOR(i, 1, n) {
//cout << " i = " << i << " j = " << j << " pal1 = " << h1.pal(i, j) << " pal2 = " << h2.pal(i, j) << endl;
//cout << " pref1 = " << h1.prefHsh(i, j) << " suf1 = " << h1.sufHsh(i, j) << endl;
/// b=0 - odd len pal, b=1 - even len pal
FOR(b, 0, 1) {
int le = 0, ri = n;
while (le < ri) {
int m = (le+ri+1)/2;
int fr = i-m, to = i+m+b;
if (fr < 1 || to > n)
ri = m - 1;
else if (h1.pal(fr, to) && h2.pal(fr, to))
le = m;
else ri = m-1;
}
if (h1.pal(i-le, i+le+b) && h2.pal(i-le, i+le+b))
proc (i-le, i+le+b);
}
}
ll ans = 0;
sort(srt.begin(), srt.end());
reverse(srt.begin(), srt.end());
for (auto p : srt) {
ll len = p.f;
ll hsh1 = p.s.f, hsh2 = p.s.s;
ll c = cnt[{hsh1, hsh2}];
//cout << " len = " << len << " c = " << c << " hsh1 = " << hsh1 << " hsh2 = " << hsh2 << endl;
ans = max(ans, len * c);
if (shorten.find({hsh1, hsh2}) != shorten.end()) {
cnt[shorten[{hsh1, hsh2}]] += c;
// cout << " sh to: " << shorten[{hsh1, hsh2}].f << " " << shorten[{hsh1, hsh2}].s << endl;
}
}
cout << ans << "\n";
return 0;
}
