#include <bits/stdc++.h>
using namespace std;
struct pal_tree {
#define sigma 26
struct node {
int len, dep, cnt, slink;
int to[sigma];
node(int _len = 0, int _dep = 0, int _cnt = 0, int _slink = 0) {
len = _len; dep = _dep; cnt = _cnt; slink = _slink;
for (int i = 0; i < sigma; i++) {
to[i] = 0;
}
}
};
int suff; string s;
vector<node> tree;
void init() {
tree.clear(); s = ""; suff = 2;
tree.push_back(node(0, 0, 0, 0));
tree.push_back(node(-1, 0, 0, 1));
tree.push_back(node(0, 0, 0, 1));
}
void add_letter(char c) {
s += c; int len = s.size();
while (c != s[len - 2 - tree[suff].len]) {
suff = tree[suff].slink;
}
int nxt = tree[suff].to[c - 'a'];
if (!nxt) {
nxt = tree.size();
tree[suff].to[c - 'a'] = nxt;
tree.push_back(node(tree[suff].len + 2, 0, 0, 0));
if (suff == 1) {
tree[nxt].slink = 2;
}
else {
int z = tree[suff].slink;
while (c != s[len - 2 - tree[z].len]) {
z = tree[z].slink;
}
tree[nxt].slink = tree[z].to[c - 'a'];
}
tree[nxt].dep = tree[tree[nxt].slink].dep + 1;
}
tree[nxt].cnt++; suff = nxt;
}
void calc_cnt() {
for (int i = tree.size() - 1; i > 2; i--) {
tree[tree[i].slink].cnt += tree[i].cnt;
}
}
node &operator[](int i) {
return tree[i];
}
} pt;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
string s; cin >> s;
pt.init();
for (char i : s) {
pt.add_letter(i);
}
pt.calc_cnt();
long long res = 0;
for (int i = pt.tree.size() - 1; i > 2; i--) {
res = max(res, (long long)(pt.tree[i].len) * pt.tree[i].cnt);
}
cout << res << endl;
return 0;
}
