#include<bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 9;
const int b = 31;
const int nax = 10003;
map<long long,int>cnt;
string s;
long long p[nax];
int n;
long long pwr[nax];
long long ans = 0;
long long get(int l, int r) {
long long ret = p[r];
if(l) ret -= p[l-1];
ret *= pwr[n-r-1];
return ret;
}
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) {
for(int j=0; ; ++j) {
if(i-j<0 || i+j>=n) break;
if(s[i-j]!=s[i+j]) break;
long long h_val = get(i-j, i+j);
cnt[h_val]++;
ans = max(ans, (j*2+1) * 1LL * cnt[h_val]);
}
}
for(int i=0; i<n-1; ++i) {
for(int j=0; ; ++j) {
if(i-j<0 || i+j+1>=n) break;
if(s[i-j]!=s[i+j+1]) break;
long long h_val = get(i-j, i+j+1);
cnt[h_val]++;
ans = max(ans, (j+1)*2LL * cnt[h_val]);
}
}
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;
}
