#include <bits/stdc++.h>
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
#define rep(i,l,r) for (int i = l; i < r; i++)
#define repr(i,r,l) for (int i = r; i >= l; i--)
#define X first
#define Y second
#define pb push_back
#define endl '\n'
#define debug(x) cerr << #x << " : " << x << endl;
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pll;
constexpr int N = 3e5+20,mod = 1e9+7,inf = 1e9+10;
inline int mkay(int a,int b){
if (a+b >= mod) return a+b-mod;
if (a+b < 0) return a+b+mod;
return a+b;
}
inline int poww(int a,int k){
if (k < 0) return 0;
int z = 1;
while (k){
if (k&1) z = 1ll*z*a%mod;
a = 1ll*a*a%mod;
k >>= 1;
}
return z;
}
int tr[N][26],n,sz[N],cur,mx,suf[N],ans[N];
string s;
inline void add_to_tree(int i){
while (i-sz[cur]-1 < 0 || s[i] != s[i-sz[cur]-1]){
cur = suf[cur];
}
int c = s[i]-'a';
if (!tr[cur][c]){
mx++;
tr[cur][c] = mx;
sz[mx] = sz[cur]+2;
int nxt = suf[cur];
while (s[i] != s[i-sz[nxt]-1]) nxt = suf[nxt];
if (sz[mx] > 1) suf[mx] = tr[nxt][c];
else suf[mx] = 1;
cur = mx;
ans[mx]++;
}
else{
cur = tr[cur][c];
ans[cur]++;
}
}
int main(){
ios :: sync_with_stdio(0); cin.tie(0);
cin >> s;
n = s.size();
sz[0] = -1;
sz[1] = 0;
cur = 1;
mx = 1;
suf[1] = 0;
suf[0] = 0;
rep(i,0,n){
add_to_tree(i);
}
ll ANS = 0;
repr(i,mx,1){
ans[suf[i]] += ans[i];
ANS = max(ANS,1ll*ans[i]*sz[i]);
}
cout << ANS;
}
