#include <bits/stdc++.h>
using namespace std;
const int N = 300005;
const int base = 5102000;
const int mod[] = {(int)1e9 + 7, (int)1e9 + 123};
int n;
int cnt;
int f[N];
int sz[N];
int pw[2][N];
int hsh[2][2][N];
long long res;
vector<int> G[N];
string s;
map< pair<int, int>, int > label;
inline int get0(int t, int l, int r) {
int ret = hsh[t][0][r] - 1LL * hsh[t][0][l - 1] * pw[t][r - l + 1] % mod[t];
if (ret < 0) ret += mod[t]; return ret;
}
inline int get1(int t, int l, int r) {
int ret = hsh[t][1][l] - 1LL * hsh[t][1][r + 1] * pw[t][r - l + 1] % mod[t];
if (ret < 0) ret += mod[t]; return ret;
}
inline pair<int, int> get0(int l, int r) {
return make_pair(get0(0, l, r), get0(1, l, r));
}
inline pair<int, int> get1(int l, int r) {
return make_pair(get1(0, l, r), get1(1, l, r));
}
void go(int l, int r) {
// cout << "# " << l << ' ' << r << '\n';
pair<int, int> tmp;
int 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();
for (int t = 0; t <= 1; ++t) {
pw[t][0] = 1;
for (int i = 1; i <= n; ++i) {
pw[t][i] = 1LL * pw[t][i - 1] * base % mod[t];
}
for (int i = 1; i <= n; ++i) {
hsh[t][0][i] = (1LL * hsh[t][0][i - 1] * base + s[i - 1] - 'a' + 1) % mod[t];
}
for (int i = n; i >= 1; --i) {
hsh[t][1][i] = (1LL * hsh[t][1][i + 1] * base + s[i - 1] - 'a' + 1) % mod[t];
}
}
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);
}
assert(cnt <= n);
dfs(0);
cout << res;
}
