#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template <class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define all(v) v.begin(), v.end()
#define logg(x) (31 - __builtin_clz(x))
#define llogg(x) (63 - __builtin_clzll(x))
#define mini(v) min_element(v.begin(), v.end())
#define maxi(v) max_element(v.begin(), v.end())
#define TIME cerr << double(clock() - st) / (double)CLOCKS_PER_SEC
#define sq(a) ((a)*(a))
#ifdef hocln
#include "deb.h"
#else
#define imie(...) ""
#define debug() cerr
#endif
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef long double ld;
typedef tuple<ll, ll, ll> triple;
typedef tuple<ll, ll, ll, ll, ll> five;
typedef unsigned long long ull;
const long long INF = 4e18;
const int inf = 2e9;
const int MN = 3e5 + 15;
const int MX = 2e6 + 15;
const long long MOD = 1e9 + 7;
//const long long MOD = 998244353;
const long double PI = 3.141592653589793238462643383279502884197;
template<typename T, typename T2> bool chmax(T& a, const T2& b) { return a < b ? a = b, 1 : 0; }
template<typename T, typename T2> bool chmin(T& a, const T2& b) { return a > b ? a = b, 1 : 0; }
template<typename T> using vector2 = vector<vector<T>>;
const int dx[] = { 0, 0, 1, -1, 1, 1, -1, -1 };
const int dy[] = { 1, -1, 0, 0 , 1, -1, 1, -1};
std::random_device rd;
std::mt19937 gen(rd());
ll random(ll low, ll high) { uniform_int_distribution<> dist(low, high); return dist(gen); }
template<typename T1, typename T2> istream& operator>>(istream& is, pair<T1, T2>& p) {
is >> p.first;
return is >> p.second;
}
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
for (auto &i: v) os << i << ' ';
return os;
}
int tc = 0;
const int N = 1e6+15;
ll ans[N];
struct node {
int next[26];
int len;
int sufflink;
int num;
int sum = 0;
};
int len;
node T[N];
string s;
int num; // node 1 - root with len -1, node 2 - root with len 0
int suff; // max suffix palindrome
bool addLetter(int pos) {
int cur = suff, curlen = 0;
int let = s[pos] - 'a';
while (true) {
curlen = T[cur].len;
if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos])
break;
cur = T[cur].sufflink;
}
if (T[cur].next[let]) {
++T[suff = T[cur].next[let]].sum;
return false;
}
num++;
suff = num;
++T[num].sum;
T[num].len = T[cur].len + 2;
T[cur].next[let] = num;
if (T[num].len == 1) {
T[num].sufflink = 2;
T[num].num = 1;
return true;
}
while (true) {
cur = T[cur].sufflink;
curlen = T[cur].len;
if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos]) {
T[num].sufflink = T[cur].next[let];
break;
}
}
T[num].num = 1 + T[T[num].sufflink].num;
return true;
}
void initTree() {
num = 2; suff = 2;
T[1].len = -1; T[1].sufflink = 1;
T[2].len = 0; T[2].sufflink = 1;
}
// sn dsu and sn sgmt
inline void solve_test() {
cin >> s;
int n = s.size();
initTree();
for(int i = 0;i < n;i++) {
addLetter(i);
}
ll rans = 0;
for(int i = num;i > 2;--i) {
T[T[i].sufflink].sum += T[i].sum;
chmax(rans, T[i].sum *1LL* T[i].len);
}
cout << rans;
}
int main()
{
//srand(chrono::steady_clock::now().time_since_epoch().count());
//freopen("convention2.in", "r", stdin);
//freopen("convention2.out", "w", stdout);
//cout << "Case #" << tc << ": " << ans << '\n';
//cout << fixed << setprecision(15);
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int tt = 1;
//cin >> tt;
while(tt--) {
++tc;
solve_test();
}
}
