#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 300'005;
struct node {
int nxt[26];
int par, len, suflink, cnt;
node() {
memset(nxt, 0, sizeof nxt);
par = len = suflink = cnt = 0;
}
} tree[N];
int nodes = 0, suf;
void build() {
nodes++;
tree[nodes].len = -1;
tree[nodes].suflink = nodes;
nodes++;
tree[nodes].len = 0;
tree[nodes].suflink = nodes - 1;
}
ll ans = 0;
int dfs(int i) {
int cnt = tree[i].cnt;
for (int j = 0; j < 26; j++) {
if (!tree[i].nxt[j]) continue;
cnt += dfs(tree[i].nxt[j]);
}
ans = max(ans, 1ll * cnt * tree[i].len);
return cnt;
}
int main() {
ios_base::sync_with_stdio(0), cin.tie(0);
string s;
cin >> s;
int n = s.size();
build();
suf = 1;
for (int i = 0; i < n; i++) {
int cur = suf;
while (i - tree[cur].len - 1 < 0 || s[i - tree[cur].len - 1] != s[i]) {
cur = tree[cur].suflink;
}
bool old = 1;
if (!tree[cur].nxt[s[i] - 'a']) {
old = 0;
nodes++;
tree[cur].nxt[s[i] - 'a'] = nodes;
tree[nodes].len = tree[cur].len + 2;
tree[nodes].par = cur;
}
int p = tree[cur].nxt[s[i] - 'a'];
tree[p].cnt++;
suf = p;
if (old) continue;
if (tree[p].len == 1) {
tree[p].suflink = 2;
continue;
}
cur = tree[cur].suflink;
while (i - tree[cur].len - 1 < 0 || s[i - tree[cur].len - 1] != s[i]) {
cur = tree[cur].suflink;
}
cur = tree[cur].nxt[s[i] - 'a'];
tree[p].suflink = cur;
}
for (int i = nodes; i >= 1; i--) {
// tree[tree[i].par].cnt += tree[i].cnt;
tree[tree[i].suflink].cnt += tree[i].cnt;
// cout << i << ": " << tree[i].len << ' ' << tree[i].cnt << ' ' << tree[i].par << ' ' << tree[i].suflink << '\n';
ans = max(ans, 1ll * tree[i].cnt * tree[i].len);
}
cout << ans << '\n';
return 0;
}
