#include <bits/stdc++.h>
using namespace std;
const int Z = 3e5+2;
int n, sz[Z] {-1}, sLink[Z], cnt[Z], cur = 2, p = 1;
map<char, int> c[Z];
string s;
int main() {
cin >> s; n = size(s);
s = '_' + s;
for(int i = 1; i <= n; ++i) {
for(; s[i-sz[p]-1] != s[i]; p = sLink[p]);
if(!c[p][s[i]]) {
int &v = (sLink[cur] = sLink[p]);
for(; s[i-sz[v]-1] != s[i]; v = sLink[v]);
v = max(1, c[v][s[i]]);
sz[cur] = sz[p] + 2;
c[p][s[i]] = cur++;
}
++cnt[p = c[p][s[i]]];
}
long long res {};
for(int u = cur; u--; ) {
res = max(res, 1LL * cnt[u] * sz[u]);
cnt[sLink[u]] += cnt[u];
}
cout << res;
}
