#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
string s;
const int CT = 3;
const ll BASE = 29;
const ll MOD[CT] = {(ll)1e9 + 7, (ll)1e9 + 9, (ll)1e9 + 13};
ll binpow(ll x, ll p, const ll mod) {
x %= mod;
p %= mod;
ll res = 1;
while (p > 0) {
if (p & 1) {
res = (res * x) % mod;
}
x = (x * x) % mod;
p >>= 1;
}
return res;
}
struct Hash {
ll val[CT];
int len;
Hash() {
for (int i=0; i<CT; ++i) {
val[i] = 0;
}
len = 0;
}
Hash(char c) {
for (int i=0; i<CT; ++i) {
val[i] = c - 'a' + 1;
}
len = 1;
}
void add_left(char c) {
for (int i=0; i<CT; ++i) {
val[i] = (val[i] * BASE) % MOD[i];
val[i] += c - 'a' + 1;
}
++len;
}
void add_right(char c) {
for (int i=0; i<CT; ++i) {
val[i] = (val[i] + c * binpow(BASE, len, MOD[i])) % MOD[i];
}
++len;
}
inline const bool operator<(const Hash& other) const {
if (len != other.len) {
return len < other.len;
}
for (int i=0; i<CT; ++i) {
if (val[i] != other.val[i]) {
return val[i] < other.val[i];
}
}
return false;
}
};
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> s;
const int N = s.size();
map<Hash, ll> ct;
for (int i=0; i<N; ++i) {
Hash hash(s[i]);
++ct[hash];
int L = i-1, R = i+1;
while (L >= 0 && R < N && s[L] == s[R]) {
hash.add_left(s[L]);
hash.add_right(s[R]);
++ct[hash];
--L; ++R;
}
hash = Hash();
L = i, R = i+1;
while (L >= 0 && R < N && s[L] == s[R]) {
hash.add_left(s[L]);
hash.add_right(s[R]);
++ct[hash];
--L; ++R;
}
}
ll ans = 0;
for (auto it=ct.begin(); it!=ct.end(); ++it) {
ans = max(ans, it->first.len * it->second);
}
cout << ans << endl;
}
