#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
const int N = 3e5+1;
const int MOD1 = 1000000007,
MOD2 = 999999937;
const int a1 = 235829684,
a2 = 398593609;
int pm(int a, int b, int mod){
if(b == 0) return 1;
return pm(a * a % mod, b / 2, mod) * (b % 2 ? a : 1) % mod;
}
int mi(int a, int mod){
return pm(a, mod - 2, mod);
}
struct StrHash{
int ha[N], pw[N], a, p;
void prec(string& s, int a, int p){
StrHash::a = a; StrHash::p = p;
pw[0] = 1; for(int i = 0; i < s.size(); i++) pw[i + 1] = pw[i] * a % p;
for(int i = 0; i < s.size(); i++){
ha[i + 1] = (ha[i] * a + s[i]) % p;
}
}
int hash(int l, int r){
int ret = ha[r + 1] - ha[l] * pw[r - l + 1];
return (ret % p + p) % p;
}
} hpf[2], hsf[2];
int n;
bool isPal(int l, int r){
bool ok = true;
for(int i = 0; i < 2; i++){
ok |= hpf[i].hash(l, r) == hsf[i].hash(n - 1 - l, n - 1 - r);
}
return ok;
}
int mx_pal[N * 2 + 1];
int32_t main(){
string s;
cin >> s;
n = s.size();
vector<tuple<int, int, int>> hashs;
hpf[0].prec(s, a1, MOD1); hpf[1].prec(s, a2, MOD2);
reverse(s.begin(), s.end());
hsf[0].prec(s, a1, MOD1); hsf[1].prec(s, a2, MOD2);
for(int i = 0; i <= (n - 1) * 2; i++){
int l = i / 2, r = (i + 1) / 2;
if(s[l] != s[r]) continue;
int ql = 0, qr = min(l - 0, n - 1 - r);
while(ql != qr){
int qm = (ql + qr + 1) / 2;
if(isPal(l - qm, r + qm)){
ql = qm;
}else{
qr = qm - 1;
}
}
mx_pal[i] = ql + 1;
}
// for(int i = 0; i <= (n - 1) * 2; i++){
// cout << mx_pal[i] << ' ';
// }
// cout << endl;
for(int i = 0; i <= (n - 1) * 2; i++){
int l = i / 2, r = (i + 1) / 2;
for(int d = 0; d < mx_pal[i]; d++){
hashs.push_back({hpf[0].hash(l - d, r + d), hpf[1].hash(l - d, r + d), (r - l + 1) + d * 2});
}
}
sort(hashs.begin(), hashs.end());
int h1 = 0, h2 = 0, cnt = 0, len = 0, ans = 0;
for(auto i : hashs){
if(get<0>(i) != h1 || get<1>(i) != h2){
h1 = get<0>(i), h2 = get<1>(i);
cnt = 1, len = get<2>(i), ans = max(ans, cnt * len);
}else{
cnt++;
ans = max(ans, cnt * len);
}
}
cout << ans << endl;
}
