#include <iostream>
#include <map>
#include <string>
#include <vector>
using namespace std;
typedef long long llong;
const int MAXN = 3e5 + 10;
const int ALPHA = 26;
struct PalindromicTree
{
int n, last, sz;
llong ans;
struct Node
{
int len, sufflink, cnt;
int nxt[ALPHA];
vector < int > adj;
Node(){};
};
char str[MAXN];
Node tree[MAXN];
PalindromicTree(){};
void init()
{
str[0] = -1;
tree[0].sufflink = 1;
tree[0].len = 0;
tree[1].sufflink = 1;
tree[1].len = -1;
sz = 2;
n = 0;
last = 1;
}
int get_par(int u)
{
while(str[n - tree[u].len - 1] != str[n])
{
u = tree[u].sufflink;
}
return u;
}
void update(char c)
{
str[++n] = c;
int letter = c - 'a';
int par = get_par(last);
if(!tree[par].nxt[letter])
{
int suff = get_par(tree[par].sufflink);
tree[sz].len = tree[par].len + 2;
tree[sz].sufflink = tree[suff].nxt[letter];
tree[sz].cnt = 1;
tree[par].nxt[letter] = sz;
tree[tree[sz].sufflink].adj.push_back(sz);
sz++;
}
else
{
tree[tree[par].nxt[letter]].cnt++;
}
last = tree[par].nxt[letter];
}
void build(string s)
{
for(int i = 0; i < s.size(); i++)
{
update(s[i]);
}
}
void dfs(int u)
{
for(int v : tree[u].adj)
{
dfs(v);
tree[u].cnt += tree[v].cnt;
}
ans = max(ans, 1LL * tree[u].cnt * tree[u].len);
}
};
PalindromicTree paltree;
string s;
int main()
{
cin >> s;
paltree.init();
paltree.build(s);
paltree.dfs(0);
cout << paltree.ans << endl;
return 0;
}
