// And you curse yourself for things you never done
#include<bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define sz(s) int((s).size())
#define bit(n,k) (((n)>>(k))&1)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 3e5 + 10, mod = 1e9 + 7, inf = 1e9 + 10;
int f[maxn], ln[maxn];
int nxt[maxn][26];
vector<int> v[maxn];
int val[maxn];
ll ANS;
int dfs(int u){
int num = val[u];
for(int y : v[u]){
num+= dfs(y);
}
ANS = max(ANS, 1ll * num * ln[u]);
return num;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie();
int C = 2;
ln[0] = -1;
ln[1] = 0;
f[1] = 0;
f[0] = 0;
string s;
cin >> s;
int tmp = 1;
for(int i = 0; i < sz(s); i++){
while(i - ln[tmp] <= 0 || s[i - ln[tmp] - 1] != s[i])
tmp = f[tmp];
if(nxt[tmp][s[i] - 'a'] == 0){
ln[C] = ln[tmp] + 2;
nxt[tmp][s[i] - 'a'] = C;
int tmp2 = f[tmp];
while(i - ln[tmp2] <= 0 || s[i - ln[tmp2] - 1] != s[i])
tmp2 = f[tmp2];
if(tmp == 0)
f[C] = 1;
else
f[C] = nxt[tmp2][s[i] - 'a'];
C++;
}
tmp = nxt[tmp][s[i] - 'a'];
val[tmp]++;
}
for(int i = 1; i < C; i++){
v[f[i]].PB(i);
}
dfs(0);
return cout << ANS << endl, 0;
}
