#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
typedef long long ll;
const ll M1 = 1e9 + 7, M2 = 1e9 + 9;
const int LM = 6e5 + 5;
ll n, r[LM], e, x, ans;
string s, t;
ll X1, X2, H[LM][2], pw[LM][2];
struct node{
ll len, l, r, cnt;
pair<ll, ll> h;
bool operator<(const node & x)const{
if(len == x.len) return h < x.h;
return len > x.len;
}
};
multiset<node> ms;
// len hash1 hash2 l r cnt
pair<ll, ll> Hash(int l, int r){
ll y1 = ((H[l][0] - H[r + 1][0] * pw[r - l + 1][0]) % M1 + M1) % M1;
ll y2 = ((H[l][1] - H[r + 1][1] * pw[r - l + 1][1]) % M2 + M2) % M2;
return {y1, y2};
}
void get_hash(string& s){
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int n = s.size();
static uniform_int_distribution<int> f(300, M1 - 1);
X1 = f(rng); X2 = f(rng);
pw[0][0] = pw[0][1] = 1;
for(int i = 1; i <= n; i++){
pw[i][0] = pw[i - 1][0] * X1 % M1;
pw[i][1] = pw[i - 1][1] * X2 % M2;
}
for(int i = n - 1; i >= 0; i--){
H[i][0] = (H[i + 1][0] * X1 + s[i]) % M1;
H[i][1] = (H[i + 1][1] * X2 + s[i]) % M2;
}
return;
}
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> t;
get_hash(t);
s += '#';
for(int i = 0; i < t.size(); i++) s += t[i], s += '#';
n = s.size();
for(int i = 0; i < n; i++){
if(i <= e) r[i] = min(r[2 * x - i], e - i);
while(i - r[i] - 1 >= 0 && i + r[i] + 1 < n && s[i - r[i] - 1] == s[i + r[i] + 1]) r[i]++;
if(i + r[i] > e){
e = i + r[i]; x = i;
}
}
for(int i = 0; i < n; i++){
int s, e = -1, m = i / 2;
if(i & 1) s = m - r[i]/2, e = m + r[i]/2;
else if(r[i]) s = m - r[i]/2, e = s + r[i] - 1;
if(e != -1) ms.insert({r[i], s, e, 1, Hash(s, e)});
}
while(ms.size()){
auto cur = *ms.begin(); ms.erase(ms.begin());
while(ms.size() && cur.h == ms.begin()->h){
cur.cnt += ms.begin()->cnt;
ms.erase(ms.begin());
}
ans = max(ans, cur.len * cur.cnt);
cur.l++; cur.r--;
if(cur.l <= cur.r){
cur.len -= 2;
cur.h = Hash(cur.l, cur.r);
ms.emplace(cur);
}
}
cout << ans << '\n';
return 0;
}
