#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/trie_policy.hpp>
// #include <ext/rope>
using namespace std;
// using namespace __gnu_cxx;
// using namespace __gnu_pbds;
void Hollwo_Pelw();
signed main(){
#ifndef hollwo_pelw_local
if (fopen("hollwo_pelw.inp", "r"))
assert(freopen("hollwo_pelw.inp", "r", stdin)), assert(freopen("hollwo_pelw.out", "w", stdout));
#else
using namespace chrono;
auto start = steady_clock::now();
#endif
cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
int testcases = 1;
// cin >> testcases;
for (int test = 1; test <= testcases; test++){
// cout << "Case #" << test << ": ";
Hollwo_Pelw();
}
#ifdef hollwo_pelw_local
auto end = steady_clock::now();
cout << "\nExecution time : " << duration_cast<milliseconds> (end - start).count() << "[ms]" << endl;
#endif
}
const int N = 3e5 + 5;
int n, siz[N], cnt[N], slink[N], tr[N][26], nnode = 1;
char s[N];
void Hollwo_Pelw(){
cin >> (s + 1), n = strlen(s + 1);
siz[0] = -1;
for (int i = 1, c = 1; i <= n; i++) {
while (s[i] != s[i - siz[c] - 1])
c = slink[c];
if (!tr[c][s[i] - 'a']) {
int p = slink[c];
while (s[i] != s[i - siz[p] - 1])
p = slink[p];
p = max(1, tr[p][s[i] - 'a']);
tr[c][s[i] - 'a'] = ++ nnode;
slink[nnode] = p, siz[nnode] = siz[c] + 2;
}
cnt[c = tr[c][s[i] - 'a']] ++;
}
long long res = 0;
for (int i = nnode; i; i--) {
cnt[slink[i]] += cnt[i];
res = max(res, 1ll * cnt[i] * siz[i]);
}
cout << res << '\n';
}
