#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
using ll = long long;
const ll mod = 998244353;
#define fi first
#define se second
#define rep(i,n) for(ll i=0;i<n;i++)
#define all(x) x.begin(),x.end()
#define faster ios::sync_with_stdio(false);cin.tie(nullptr)
ll modpow(ll A,ll N){
ll res=1;
while(N){
if(N&1) res=res*A%mod;
A=A*A%mod;
N>>=1;
}
return res;
}
ll modinv(ll A){return modpow(A,mod-2);}
int main() {
string s;
cin >> s;
ll N=s.size();
if(N>10000) return 0;
vector<ll> A(N+1),B(N+1);
A[0]=0;
B[N]=0;
ll k=1;
rep(i,N) A[i+1]=(A[i]+(s[i]-'a'+1)*k)%mod,k=k*100%mod;
k=1;
for(ll i=N-1;i>=0;i--) B[i]=(B[i+1]+(s[i]-'a'+1)*k)%mod,k=k*100%mod;
vector<ll> inv(N);
inv[0]=1;
rep(i,N-1) inv[i+1]=inv[i]*828542813%mod;
unordered_map<ll,ll> M;
ll ans=0;
for(ll i=0;i<N;i++){
for(ll j=i;j<N;j++){
if((A[j+1]-A[i]+mod)*(inv[i])%mod==(B[i]-B[j+1]+mod)*(inv[N-j-1])%mod){
M[(A[j+1]-A[i]+mod)*(inv[i])%mod]+=j-i+1;
ans=max(ans,M[(B[i]-B[j+1]+mod)%mod]);
}
}
}
cout << ans << endl;
return 0;
}
