#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int Nmax = 1e6 + 5;
struct tr
{
int len, sufflink, cnt;
map<char, int> go;
};
string S;
class PalindromicTree
{
int nodes, suff;
tr a[Nmax];
public:
void init()
{
nodes = 2;
a[1].len = -1;
a[1].sufflink = 1;
a[1].cnt = 0;
a[2].len = 0;
a[2].sufflink = 1;
a[2].cnt = 0;
suff = 2;
}
void add(char c, int pos)
{
int act = a[suff].len, node = suff;
while(pos-act-1<0 || S[pos] != S[pos - act - 1])
{
node = a[node].sufflink;
act = a[node].len;
}
if(a[node].go[c])
{
suff = a[node].go[c];
++a[suff].cnt;
return;
}
a[node].go[c] = ++nodes;
a[nodes].len = a[node].len + 2;
a[nodes].cnt = 1;
suff = nodes;
if(a[nodes].len == 1)
{
a[nodes].sufflink = 2;
return;
}
node = a[node].sufflink;
act = a[node].len;
while(pos-act-1<0 || S[pos] != S[pos - act - 1])
{
node = a[node].sufflink;
act = a[node].len;
}
a[nodes].sufflink = a[node].go[c];
}
int get_result()
{
int i;
ll ans = 0;
for(i=nodes; i; --i)
a[a[i].sufflink].cnt += a[i].cnt;
for(i=3; i<=nodes; ++i)
ans = max(ans, (ll) a[i].cnt * a[i].len);
return ans;
}
} paltree;
int main()
{
// freopen("input", "r", stdin);
cin.sync_with_stdio(false);
paltree.init();
cin >> S;
int nr = 0;
for(auto letter : S)
paltree.add(letter, nr++);
cout << paltree.get_result() << '\n';
return 0;
}
