#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include <time.h>
#endif
#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) \
{ \
++recur_depth; \
auto x_ = x; \
--recur_depth; \
cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":" \
<< __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl; \
}
#else
#define dbg(x)
#endif
using namespace std;
using namespace __gnu_pbds;
typedef pair<int, int> ii;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
tree_order_statistics_node_update>;
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
!is_same<T_container, string>::value,
typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
os << '{';
string sep;
for (const T &x : v)
os << sep << x, sep = ", ";
return os << '}';
}
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;
const int MAXN = 3e5 + 10;
// Saw Solution
struct PalindromeTree {
struct Node {
ll label[26], suff, len, cnt_suff;
vi eds;
Node() {
for (int i=0; i<26; i++) label[i] = -1;
}
} tree[MAXN + 100];
string s;
int curr_node, cnt_node;
void init(string s_) {
tree[0].len = -1;
tree[0].suff = 0;
tree[1].len = 0;
tree[1].suff = 0;
tree[0].eds.push_back(1);
curr_node = cnt_node = 1;
s = s_;
for (int i=0; i<s.size(); i++) add(i);
}
void add(int idx) {
int curr = curr_node;
int c = s[idx] - 'a';
while (1) {
if (idx - tree[curr].len - 1 >= 0 && s[idx - tree[curr].len - 1] == s[idx]) break;
curr = tree[curr].suff;
}
if (tree[curr].label[c] != -1) {
curr_node = tree[curr].label[c];
tree[curr_node].cnt_suff++;
return;
}
curr_node = ++cnt_node;
tree[curr].label[c] = curr_node;
tree[curr_node].len = tree[curr].len + 2;
tree[curr_node].cnt_suff = 1;
if (curr == 0) {
tree[curr_node].suff = 1;
tree[1].eds.push_back(curr_node);
return;
}
while (1) {
curr = tree[curr].suff;
if (idx - tree[curr].len - 1 >= 0 && s[idx - tree[curr].len - 1] == s[idx]) {
tree[curr_node].suff = tree[curr].label[c];
tree[tree[curr].label[c]].eds.push_back(curr_node);
break;
}
}
}
ll get_score() {
ll ans = -INF;
function<void(int)> f = [&](int u) {
for (int &v : tree[u].eds) {
f(v);
tree[u].cnt_suff += tree[v].cnt_suff;
}
ans = max(ans, tree[u].cnt_suff * tree[u].len);
}; f(0);
return ans;
}
} pt;
void solve() {
string s; cin >> s;
pt.init(s);
cout << pt.get_score() << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
clock_t start = clock();
int test_cases = 1;
/* cin >> test_cases; */
while (test_cases--)
solve();
#ifdef DEBUG
cerr << fixed << setprecision(10)
<< "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
<< "s\n";
#endif
return 0;
}
