#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// #include <ext/rope>
using namespace std;
// using namespace __gnu_pbds;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef long double ld;
template <class T>
using VV = vector<vector<T>>;
using VI = vector<int>;
using VVI = vector<vector<int>>;
using VL = vector<long long>;
using VVL = vector<vector<long long>>;
using VC = vector<char>;
using VVC = vector<vector<char>>;
using VB = vector<bool>;
using VVB = vector<vector<bool>>;
using VD = vector<double>;
using VVD = vector<vector<double>>;
using PII = pair<int, int>;
using PLL = pair<long long, long long>;
using PIL = pair<int, long long>;
using PLI = pair<long long, int>;
using VPII = vector<pair<int, int>>;
using VPLL = vector<pair<long long, long long>>;
#define LINE '\n'
#define SPACE ' '
#define PB push_back
#define FOR(i, a, b) for (int i = (a); i < (int(b)); i++)
#define FORE(i, a, b) for (int i = (a); i <= (int)((b)); i++)
#define ALL(x) x.begin(), x.end()
#define RALL(x) x.rbegin(), x.rend()
#define sq(a) ((a) * (a))
#define sz(x) ((int)x.size())
#define fastio() \
ios_base::sync_with_stdio(false); \
cin.tie(nullptr); \
cout.tie(nullptr)
#define debug(x) cerr << #x << " = " << x << endl;
const ll MOD = 51123987;
template <class T>
inline void maxi(T &a, T b)
{
a = max(a, b);
}
template <class T>
inline void mini(T &a, T b)
{
a = min(a, b);
}
template <class T>
inline void addi(T &a, T b)
{
a = (a + b) % MOD;
}
template <class T>
inline void subi(T &a, T b)
{
a = (a - b + MOD) % MOD;
}
template <class T>
inline T add(T a, T b)
{
return (a + b) % MOD;
}
template <class T>
inline T sub(T a, T b)
{
return (a - b + MOD) % MOD;
}
template <class T>
inline T mul(T a, T b)
{
return ((a % MOD) * (b % MOD)) % MOD;
}
constexpr ll binpow(ll a, ll b, ll mod)
{
ll res = 1;
while (b > 0)
{
if (b & 1)
{
res = (res * a) % mod;
}
a = (a * a) % mod;
b >>= 1;
}
return res;
}
const int INF = 1e9;
const int MAX_N = 1e5 + 3;
VI z_function(string s)
{
int n = sz(s);
VI z(n);
int L = 0, R = 0;
FOR(i, 1, n)
{
if (i <= R)
z[i] = min(R - i + 1, z[i - L]);
while (i + z[i] < n && s[z[i]] == s[i + z[i]])
z[i]++;
if (i + z[i] - 1 > R)
{
L = i;
R = i + z[i] - 1;
}
}
return z;
}
VI manacher_d1(string s)
{
int n = sz(s);
VI d1(n);
int l = 0, r = 0;
FOR(i, 0, n)
{
int k = 1;
if (i <= r)
{
int j = l + r - i;
k = min(d1[j], r - i + 1);
}
while (i - k >= 0 && i + k < n && s[i - k] == s[i + k])
k++;
d1[i] = k;
if (i + k - 1 > r)
{
l = i - k + 1;
r = i + k - 1;
}
}
return d1;
}
VI manacher_d2(string s)
{
int n = sz(s);
VI d2(n);
int l = 0, r = -1;
FOR(i, 0, n)
{
int k = 0;
if (i <= r)
{
int j = l + r - i + 1;
k = min(d2[j], r - i + 1);
}
while (i - k - 1 >= 0 && i + k < n && s[i - k - 1] == s[i + k])
k++;
d2[i] = k;
if (i + k - 1 > r)
{
l = i - k;
r = i + k - 1;
}
}
return d2;
}
struct PTree
{
struct Node
{
int len;
int link;
array<int, 26> next;
ll cnt;
Node(int _len = 0, int _link = 0) : len(_len), link(_link), cnt(0)
{
next.fill(-1);
}
};
string s;
vector<Node> tree;
int last;
void init()
{
s.clear();
tree.clear();
tree.push_back(Node{-1, 0});
tree.push_back(Node{0, 0});
tree[0].link = -1;
tree[1].link = 0;
last = 1;
}
void extend(char c)
{
int pos = sz(s);
s.push_back(c);
int cur = last;
while (true)
{
int len = tree[cur].len;
if (pos - 1 - len >= 0 && s[pos - 1 - len] == c)
break;
cur = tree[cur].link;
}
if (tree[cur].next[c - 'a'] != -1)
{
last = tree[cur].next[c - 'a'];
tree[last].cnt++;
return;
}
int id = (int)tree.size();
tree[cur].next[c - 'a'] = id;
tree.push_back(Node{tree[cur].len + 2, 0});
last = id;
tree[last].cnt = 1;
if (tree[last].len == 1)
{
tree[last].link = 1;
return;
}
cur = tree[cur].link;
while (true)
{
int len = tree[cur].len;
if (pos - 1 - len >= 0 && s[pos - 1 - len] == c)
{
tree[last].link = tree[cur].next[c - 'a'];
break;
}
cur = tree[cur].link;
}
}
void build(string &inp)
{
init();
FOR(i, 0, sz(inp))
{
char c = inp[i];
extend(c);
}
for (int i = sz(tree) - 1; i >= 2; i--)
{
int par = tree[i].link;
tree[par].cnt += tree[i].cnt;
}
}
};
void solve()
{
string s;
cin >> s;
PTree ptree;
ptree.build(s);
ll ans = 0;
FOR(i, 2, sz(ptree.tree))
{
// debug(ptree.tree[i].cnt);
// debug(ptree.tree[i].len);
maxi(ans, ptree.tree[i].cnt * ptree.tree[i].len);
}
cout << ans << LINE;
}
int main()
{
fastio();
int t = 1;
// cin >> t;
while (t--)
solve();
}
