#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,pair<ll, ll>>, ll> cnt;
unordered_map<ll, ll> toLen;
unordered_map<ll, ll> cnt;
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) FOR(j, i, 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;
if (h1.pal(i, j) && h2.pal(i, j)) {
//cnt[{j-i+1, {h1.prefHsh(i, j), h2.prefHsh(i, j)}}]++;
ll h = h1.prefHsh(i, j);
cnt[h]++;
toLen[h] = j-i+1;
}
}
ll ans = 0;
for (auto p : cnt) {
ll len = toLen[p.f];
ll c = p.s;
ans = max(ans, len*c);
}
cout << ans << "\n";
return 0;
}
