#include <iostream>
#include <vector>
#include <tuple>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <map>
#include <cmath>
#include <random>
#include <string>
#include <bitset>
#include <cassert>
#include <climits>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
using namespace std;
#define ll long long
#define f first
#define s second
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template<typename A> void __print(const A &x);
template<typename A, typename B> void __print(const pair<A, B> &p);
template<typename... A> void __print(const tuple<A...> &t);
template<typename T> void __print(stack<T> s);
template<typename T> void __print(queue<T> q);
template<typename T, typename... U> void __print(priority_queue<T, U...> q);
template<typename A> void __print(const A &x) {
bool first = true;
cerr << '{';
for (const auto &i : x) {
cerr << (first ? "" : ","), __print(i);
first = false;
}
cerr << '}';
}
template<typename A, typename B> void __print(const pair<A, B> &p) {
cerr << '(';
__print(p.f);
cerr << ',';
__print(p.s);
cerr << ')';
}
template<typename... A> void __print(const tuple<A...> &t) {
bool first = true;
cerr << '(';
apply([&first] (const auto &...args) { ((cerr << (first ? "" : ","), __print(args), first = false), ...); }, t);
cerr << ')';
}
template<typename T> void __print(stack<T> s) {
vector<T> debugVector;
while (!s.empty()) {
T t = s.top();
debugVector.push_back(t);
s.pop();
}
reverse(debugVector.begin(), debugVector.end());
__print(debugVector);
}
template<typename T> void __print(queue<T> q) {
vector<T> debugVector;
while (!q.empty()) {
T t = q.front();
debugVector.push_back(t);
q.pop();
}
__print(debugVector);
}
template<typename T, typename... U> void __print(priority_queue<T, U...> q) {
vector<T> debugVector;
while (!q.empty()) {
T t = q.top();
debugVector.push_back(t);
q.pop();
}
__print(debugVector);
}
void _print() { cerr << "]\n"; }
template <typename Head, typename... Tail> void _print(const Head &H, const Tail &...T) {
__print(H);
if (sizeof...(T)) cerr << ", ";
_print(T...);
}
#ifdef DEBUG
#define D(...) cerr << "Line: " << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; _print(__VA_ARGS__)
#else
#define D(...)
#endif
struct Node {
int nxt[30], suffLink;
ll len, cnt;
vector<int> edges;
} tree[300005];
string s;
int suff, idx;
ll ans;
void addLetter(int pos) {
int curr = suff, currLen = 0, let = s[pos] - 'a';
while (true) {
currLen = tree[curr].len;
if (pos - 1 - currLen >= 0 && s[pos - 1 - currLen] == s[pos]) {
break;
}
curr = tree[curr].suffLink;
}
if (tree[curr].nxt[let]) {
suff = tree[curr].nxt[let];
tree[suff].cnt++;
return;
}
idx++;
suff = idx;
tree[idx].len = tree[curr].len + 2;
tree[idx].cnt = 1;
tree[curr].nxt[let] = idx;
if (tree[idx].len == 1) {
tree[idx].suffLink = 2;
tree[2].edges.push_back(idx);
return;
}
while (true) {
curr = tree[curr].suffLink;
currLen = tree[curr].len;
if (pos - 1 - currLen >= 0 && s[pos - 1 - currLen] == s[pos]) {
tree[idx].suffLink = tree[curr].nxt[let];
tree[tree[curr].nxt[let]].edges.push_back(idx);
break;
}
}
}
void dfs(int curr) {
for (int i : tree[curr].edges) {
dfs(i);
tree[curr].cnt += tree[i].cnt;
}
ans = max(ans, tree[curr].cnt * tree[curr].len);
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> s;
idx = 2, suff = 2;
tree[1].len = -1, tree[1].suffLink = 1;
tree[2].len = 0, tree[2].suffLink = 1;
tree[1].edges.push_back(2);
for (int i = 0; i < s.length(); i++) {
addLetter(i);
}
dfs(1);
cout << ans << "\n";
}
