#include<bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 9;
const int b = 31;
const int nax = 10003;
unordered_map<long long,int>cnt[nax];
string s;
long long p[nax];
int n;
long long pwr[nax];
long long ans = 0;
void PlayGround() {
cin>>s;
n = s.size();
long long pw = 1;
for(int i=0; i<n; ++i) {
pwr[i] = pw;
p[i] = (pw * (s[i]-'a'+1));
if(i) p[i] += p[i-1];
p[i] %= mod;
pw = (pw * b) % mod;
}
for(int i=0; i<n; ++i) {
bool ok1 = 1, ok2 = 1;
for(int j=0, len=1; ; ++j, len+=2) {
if(i-j<0 || i+j>=n) break;
if(s[i-j]!=s[i+j]) {
ok1 = 0;
}
if(i+j+1>=n) ok2 = 0;
if(ok2 && s[i-j]!=s[i+j+1]) {
ok2 = 0;
}
if(!ok1 && !ok2) break;
if(ok1) {
long long h_val = p[i+j];
if(i-j) h_val -= p[i-j-1];
h_val *= pwr[n-1-(i+j)];
h_val %= mod;
if(h_val<0) h_val += mod;
long long app = ++cnt[len][h_val];
ans = max(ans, len * app);
}
if(ok2) {
long long h_val = p[i+j+1];
if(i-j) h_val -= p[i-j-1];
h_val *= pwr[n-1-(i+j+1)];
h_val %= mod;
if(h_val<0) h_val += mod;
long long app = ++cnt[len+1][h_val];
ans = max(ans, (1+len) * app);
}
}
}
cout<<ans<<'\n';
cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
PlayGround();
return 0;
}
