#include <bits/stdc++.h>
using namespace std;
const int N = 300005;
const int base = 29;
const int mod = 1e9 + 9;
int n;
int cnt;
int f[N];
int sz[N];
int pw[N];
int hsh[2][N];
long long res;
vector<int> G[N];
string s;
map<int, int> label;
inline int get0(int l, int r) {
int ret = hsh[0][r] - 1LL * hsh[0][l - 1] * pw[r - l + 1] % mod;
if (ret < 0) ret += mod; return ret;
}
inline int get1(int l, int r) {
int ret = hsh[1][l] - 1LL * hsh[1][r + 1] * pw[r - l + 1] % mod;
if (ret < 0) ret += mod; return ret;
}
void go(int l, int r) {
// cout << "# " << l << ' ' << r << '\n';
int tmp, id, lst;
tmp = get0(l, r), id = label[tmp];
if (!id) {
label[tmp] = id = ++cnt;
sz[id] = r - l + 1, f[id]++;
lst = id, l++, r--;
}
else {
f[id]++; return;
}
while (l <= r) {
tmp = get0(l, r), id = label[tmp];
if (!id) {
label[tmp] = id = ++cnt;
sz[id] = r - l + 1;
G[id].push_back(lst);
lst = id, l++, r--;
}
else {
G[id].push_back(lst);
return;
}
}
if (l > r) G[0].push_back(lst);
}
void dfs(int u) {
for (auto v : G[u]) {
dfs(v), f[u] += f[v];
}
res = max(res, 1LL * sz[u] * f[u]);
}
int main() {
ios::sync_with_stdio(false);
cin >> s, n = s.size();
pw[0] = 1;
for (int i = 1; i <= n; ++i) {
pw[i] = 1LL * pw[i - 1] * base % mod;
}
for (int i = 1; i <= n; ++i) {
hsh[0][i] = (1LL * hsh[0][i - 1] * base + s[i - 1] - 'a' + 1) % mod;
}
for (int i = n; i >= 1; --i) {
hsh[1][i] = (1LL * hsh[1][i + 1] * base + s[i - 1] - 'a' + 1) % mod;
}
for (int i = 1; i <= n; ++i) {
int l, r;
l = 1, r = min(i, n - i + 1);
while (l < r) {
int mid = (l + r + 1) >> 1;
if (get0(i - mid + 1, i) == get1(i, i + mid - 1)) l = mid;
else r = mid - 1;
}
go(i - l + 1, i + l - 1);
l = 0, r = min(i, n - i);
while (l < r) {
int mid = (l + r + 1) >> 1;
if (get0(i - mid + 1, i) == get1(i + 1, i + mid)) l = mid;
else r = mid - 1;
}
if (l) go(i - l + 1, i + l);
}
dfs(0);
cout << res;
}
