#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define SZ(x) int(x.size())
#define pb push_back
#define all(x) x.begin(), x.end()
#define maxs(a, b) (a = max(a,b))
const int MXN = 3e5+5;
struct node {
int ch[26], suflnk, sz;
node() { memset(ch, -1, sizeof(ch)); suflnk=0; sz=0;}
} tree[MXN];
// 0 : -1, 1 : 0
int N = 2;
int id[MXN], dp[MXN];
vector<int> g[MXN];
void dfs(int v) {
for(int u : g[v]) {
dfs(u);
dp[v] += dp[u];
}
}
int32_t main() {
cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);
tree[0].sz = -1;
string s;
cin >> s;
int n = SZ(s);
id[0] = N++;
tree[0].ch[s[0]-'a'] = id[0];
tree[id[0]].sz=1;
dp[id[0]]++;
g[0].pb(id[0]);
for(int i=1, v; i<n; i++) {
v = id[i-1];
while(v) {
if(tree[v].sz<i && s[i-tree[v].sz-1]==s[i]) break;
v = tree[v].suflnk;
}
if(v) {
id[i] = (tree[v].ch[s[i]-'a']==-1 ? N++ : tree[v].ch[s[i]-'a']);
tree[v].ch[s[i]-'a'] = id[i];
tree[id[i]].sz = tree[v].sz+2;
v = tree[v].suflnk;
while(v) {
if(s[i-tree[v].sz-1]==s[i]) break;
v = tree[v].suflnk;
}
if(v) tree[id[i]].suflnk = tree[v].ch[s[i]-'a'];
else if(s[i-1]==s[i]) tree[id[i]].suflnk = tree[1].ch[s[i]-'a'];
else tree[id[i]].suflnk = tree[0].ch[s[i]-'a'];
}
else if(s[i-1]==s[i]) {
id[i] = (tree[1].ch[s[i]-'a']==-1 ? N++ : tree[1].ch[s[i]-'a']);
tree[1].ch[s[i]-'a'] = id[i];
tree[id[i]].sz = 2;
tree[id[i]].suflnk = tree[0].ch[s[i]-'a'];
}
else {
id[i] = (tree[0].ch[s[i]-'a']==-1 ? N++ : tree[0].ch[s[i]-'a']);
tree[0].ch[s[i]-'a'] = id[i];
tree[id[i]].sz = 1;
}
dp[id[i]]++;
g[tree[id[i]].suflnk].pb(id[i]);
}
for(int i=0; i<N; i++) {
sort(all(g[i]));
g[i].resize(unique(all(g[i]))-g[i].begin());
}
dfs(0);
ll ans=0;
for(int i=0; i<N; i++)
maxs(ans, (ll)tree[i].sz*dp[i]);
cout << ans << '\n';
return 0;
}
