#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define per(i, a, b) for (int i = b - 1; i >= (a); --i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define umap unordered_map
#define uset unordered_set
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;
const int INF = 1000000007;
const int MAXN = 305000;
struct node {
int next[26];
int len;
int sufflink;
int num;
};
int len;
string s;
node tree[MAXN];
int num; // node 1 - root with len -1, node 2 - root with len 0
int suff; // max suffix palindrome
long long ans;
bool addLetter(int pos) {
int cur = suff, curlen = 0;
int let = s[pos] - 'a';
while (true) {
curlen = tree[cur].len;
if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos])
break;
cur = tree[cur].sufflink;
}
if (tree[cur].next[let]) {
suff = tree[cur].next[let];
return false;
}
num++;
suff = num;
tree[num].len = tree[cur].len + 2;
tree[cur].next[let] = num;
if (tree[num].len == 1) {
tree[num].sufflink = 2;
tree[num].num = 1;
return true;
}
while (true) {
cur = tree[cur].sufflink;
curlen = tree[cur].len;
if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos]) {
tree[num].sufflink = tree[cur].next[let];
break;
}
}
tree[num].num = 1 + tree[tree[num].sufflink].num;
return true;
}
void initTree() {
num = 2; suff = 2;
tree[1].len = -1; tree[1].sufflink = 1;
tree[2].len = 0; tree[2].sufflink = 1;
}
int main() {
//assert(freopen("input.txt", "r", stdin));
//assert(freopen("output.txt", "w", stdout));
int cnt[MAXN];
memset(cnt, 0, sizeof(cnt));
cin>>s;
len = sz(s);
initTree();
ll ans2 = 0;
for (int i = 0; i < len; i++) {
addLetter(i);
++cnt[suff];
}
per(i, 2, num+1) {
ans2 = max(ans2, tree[i].len * ll(cnt[i]));
cnt[tree[i].sufflink] += cnt[i];
}
cout << ans2 << endl;
return 0;
}
