#include <bits/stdc++.h>
#define FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define mp make_pair
#define xx first
#define yy second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define all(x) x.begin(),x.end()
#define ff(i,a,b) for (int i = a; i < b; i++)
#define fff(i,a,b) for (int i = a; i <= b; i++)
#define bff(i,a,b) for (int i = b-1; i >= a; i--)
#define bfff(i,a,b) for (int i = b; i >= a; i--)
using namespace std;
long double typedef ld;
unsigned int typedef ui;
long long int typedef li;
pair<int,int> typedef pii;
pair<li,li> typedef pli;
pair<ld,ld> typedef pld;
vector<vector<int>> typedef graph;
unsigned long long int typedef ull;
//const int mod = 998244353;
//const int mod = 1000000007;
//Note to self: Check for overflow
int power(int a, int n, int mod)
{
li c=1;
while (n)
{
if (n&1) (c*=a)%mod;
a=(li)a*a%mod,n>>=1;
}
return c;
}
struct hesiranje
{
int p,mod;
int w[26];
void setprost(int _)
{
p=_;
}
void setmod(int _)
{
mod=_;
}
int ps[10004],pi[10004];
int pre[10004],suf[10004];
void build(string s, int n)
{
mt19937 rng(time(NULL));
ff(i,0,26) w[i]=rng()%mod;
ps[0]=1,pi[0]=1;
fff(i,1,n) ps[i]=(li)ps[i-1]*p%mod;
fff(i,1,n) pi[i]=power(ps[i],mod-2,mod);
fff(i,1,n) pre[i]=((li)pre[i-1]*p+w[s[i-1]-'a'])%mod;
bfff(i,1,n) suf[i]=((li)suf[i+1]*p+w[s[i-1]-'a'])%mod;
}
int Hash(int l, int r)
{
return (pre[r]+mod-(li)pre[l-1]*ps[r-l+1]%mod)%mod;
}
int rHash(int l, int r)
{
return (suf[l]+mod-(li)suf[r+1]*ps[r-l+1]%mod)%mod;
}
} h1,h2;
int main()
{
FAST;
string s; cin>>s;
int n=(int)s.size();
h1.setprost(1000003),h1.setmod(998244353);
h2.setprost(998244353),h2.setmod(1000000007);
h1.build(s,n),h2.build(s,n);
li ans=0;
fff(k,1,n)
{
unordered_map<li,int> kolko;
fff(i,k,n) if (h1.Hash(i-k+1,i)==h1.rHash(i-k+1,i) && h2.Hash(i-k+1,i)==h2.rHash(i-k+1,i))
{
li sta=(li)h1.Hash(i-k+1,i)*(1ll<<30) + h2.Hash(i-k+1,i);
kolko[sta]++;
}
for (auto it : kolko) ans=max(ans,(li)it.yy*k);
}
cout<<ans<<"\n";
}
//Note to self: Check for overflow
