#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<int MOD>
struct ModInt {
unsigned x;
ModInt() : x(0) { }
ModInt(signed sig) : x(sig%MOD) { }
ModInt(signed long long sig) : x(sig%MOD) { }
int get() const { return (int)x; }
ModInt pow(long long p) { ModInt res = 1, a = *this; while (p) { if (p & 1) res *= a; a *= a; p >>= 1; } return res; }
ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; }
ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
ModInt &operator/=(ModInt that) { return (*this) *= that.pow(MOD - 2); }
ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }
bool operator<(ModInt that) const { return x < that.x; }
friend ostream& operator<<(ostream &os, ModInt a) { os << a.x; return os; }
};
#define send {ios_base::sync_with_stdio(false);}
#define help {cin.tie(NULL); cout.tie(NULL);}
#define fs first
#define sc second
#define unique(v) {sort(v.begin(), v.end()); v.erase(unique(v.begin(), v.end()), v.end());}
#define endl '\n'
#define sz(x) ((int)x.size())
#define all(a) (a).begin(), (a).end()
typedef long long ll;
typedef long double ld;
typedef ModInt<1000000007> mint;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> oset;
const int mxn=200000;
// const ll mod=1000000007;
const ll INF=1000000000000000000;
template<typename A, typename B> istream& operator>>(istream& cin, pair<A, B> &p) {
cin >> p.fs;
return cin >> p.sc;
}
#define MAXLEN 1000010
constexpr uint64_t mod = (1ULL << 61) - 1;
const uint64_t seed = chrono::system_clock::now().time_since_epoch().count();
const uint64_t base = mt19937_64(seed)() % (mod / 3) + (mod / 3);
uint64_t base_pow[MAXLEN];
int64_t modmul(uint64_t a, uint64_t b){
uint64_t l1 = (uint32_t)a, h1 = a >> 32, l2 = (uint32_t)b, h2 = b >> 32;
uint64_t l = l1 * l2, m = l1 * h2 + l2 * h1, h = h1 * h2;
uint64_t ret = (l & mod) + (l >> 61) + (h << 3) + (m >> 29) + (m << 35 >> 3) + 1;
ret = (ret & mod) + (ret >> 61);
ret = (ret & mod) + (ret >> 61);
return ret - 1;
}
void init(){
base_pow[0] = 1;
for (int i = 1; i < MAXLEN; i++){
base_pow[i] = modmul(base_pow[i - 1], base);
}
}
struct PolyHash{
/// Remove suff vector and usage if reverse hash is not required for more speed
vector<int64_t> pref, suff;
PolyHash() {}
template <typename T>
PolyHash(const vector<T>& ar){
if (!base_pow[0]) init();
int n = ar.size();
assert(n < MAXLEN);
pref.resize(n + 3, 0), suff.resize(n + 3, 0);
for (int i = 1; i <= n; i++){
pref[i] = modmul(pref[i - 1], base) + ar[i - 1] + 997;
if (pref[i] >= mod) pref[i] -= mod;
}
for (int i = n; i >= 1; i--){
suff[i] = modmul(suff[i + 1], base) + ar[i - 1] + 997;
if (suff[i] >= mod) suff[i] -= mod;
}
}
PolyHash(const char* str)
: PolyHash(vector<char> (str, str + strlen(str))) {}
uint64_t get_hash(int l, int r){
int64_t h = pref[r + 1] - modmul(base_pow[r - l + 1], pref[l]);
return h < 0 ? h + mod : h;
}
uint64_t rev_hash(int l, int r){
int64_t h = suff[l + 1] - modmul(base_pow[r - l + 1], suff[r + 2]);
return h < 0 ? h + mod : h;
}
};
string FileS="";
bool tstc=0;
void dothethingthatfindsthesolutiontotheproblem(){
string s;
cin>>s;
vector<char>c;
for(auto &i:s)c.push_back(i);
PolyHash h=PolyHash(c);
map<ll,ll>mp;
ll ans=0;
for(int i=0;i<sz(s);i++){;
for(int w=i;w<sz(s);w++){
mp[h.get_hash(i,w)]++;
}
}
for(int i=0;i<sz(s);i++){
int l=i,r=i;
while(l>=0&&r<sz(s)&&s[l]==s[r]){
ans=max(ans,mp[h.get_hash(l,r)]*(r-l+1));
r++;
l--;
}
}
for(int i=1;i<sz(s);i++){
int l=i-1,r=i;
while(l>=0&&r<sz(s)&&s[l]==s[r]){
ans=max(ans,mp[h.get_hash(l,r)]*(r-l+1));
r++;
l--;
}
}
cout<<ans;
}
void File(){
ifstream cin(FileS + ".in");
ofstream cout(FileS + ".out");
}
int main(){
send help
if(FileS.size())File();
int tc=1;
if(tstc)cin>>tc;
while(tc--){
dothethingthatfindsthesolutiontotheproblem();
}
}
