#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(a) a.begin(),a.end()
const int maxn = 1e4+10;
const int MOD = 1e9+7;
ll pw[maxn], h[maxn], h2[maxn], A = 9973;
string s;
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
unordered_map<int, int, custom_hash> M;
void comp_hash(string s, ll h[])
{
h[0] = 1;
for(int i = 0; i < (int)s.size(); i++)
h[i+1] = ((h[i]*A)%MOD+s[i])%MOD;
}
inline int get_hash(int a, int b, ll h[]){
return h[b+1]-(h[a]*pw[b-a+1])%MOD;
}
inline int mir(int ind){return (int)s.size()-ind-1;}
inline bool ispal(int i, int j){
int mid = (i+j)/2;
return(i==j or get_hash(i,mid-(j-i+1)%2,h)==get_hash(mir(j),mir(mid+1),h2));
}
int32_t main()
{
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> s; pw[0] = 1;
for(int i = 1; i<maxn; i++) pw[i] = (pw[i-1]*A)%MOD;
int ans = 0, n = (int)s.size();
comp_hash(s,h); reverse(all(s)); comp_hash(s,h2);
for(int l = n; l >= 1; l--){
for(int i = 0; i+l-1 < n; i++){
int j = i+l-1;
if(ans > (j-i+1)*(n-(j-i+1)+1)) break;
if(!ispal(i,j)) continue;
M[get_hash(i,j,h)]+=j-i+1;
ans = max(ans, M[get_hash(i,j,h)]);
}
}
cout << ans << "\n";
}
