#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("sse")
#pragma loop-opt(on)
#define rep(i, a, b) for(int i = a; i <= b; i ++)
#define rrep(i, a, b) for(int i = b; i >= a; i --)
#define all(x) x.begin(), x.end()
#define ceil(a, b) ((a + b - 1) / (b))
#define int long long int
#define lld long double
#define pii pair<int, int>
#define random mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count())
#define INF 1000000000000000000
#define MOD 1000000007
#define eps (1e-9)
using namespace std;
#ifdef wiwihorz
#define print(a...)cerr<<"Line "<<__LINE__<<":",kout("["+string(#a)+"] = ", a)
void vprint(auto L,auto R){while(L<R)cerr<<*L<<" \n"[next(L) == R], ++L; }
void kout() { cerr << endl; }
template<class T1,class ... T2>void kout(T1 a,T2 ... e){cerr<<a<<" ",kout(e...);}
#else
#define print(...) 0
#define vprint(...) 0
#endif
namespace solver {
struct node {
vector<int>ch;
int suf, num, len;
node() {
ch.assign(26, 0);
suf = 1;
num = 0;
len = 0;
}
};
const int P = 300005;
vector<node> v(P, node());
string s;
int ii, suf, n;
void init_(int _n, string _s) {
n = _n, s = _s;
ii = 2, suf = 2;
v[1].len = -1;
v[2].len = 0;
}
void add(int pos) {
int cur = suf, val = s[pos] - 'a';
while(true) {
if(pos - v[cur].len - 1 >= 0 &&
s[pos - v[cur].len - 1] == s[pos]) break;
cur = v[cur].suf;
}
if(v[cur].ch[val]) {
suf = v[cur].ch[val];
v[suf].num += 1;
return;
}
ii++, suf = ii;
v[cur].ch[val] = ii;
v[ii].num = 1;
v[ii].len = v[cur].len + 2;
if(v[ii].len == 1) {
v[ii].suf = 2;
return;
}
cur = v[cur].suf;
while(true) {
if(pos - v[cur].len - 1 >= 0 &&
s[pos - v[cur].len - 1] == s[pos]) break;
cur = v[cur].suf;
}
v[ii].suf = v[cur].ch[val];
return;
}
void solve() {
rep(i, 0, n - 1) add(i);
rrep(i, 1, ii) {
int val = v[i].num;
v[v[i].suf].num += val;
}
int ans = 0;
rep(i, 3, ii) ans = max(ans, v[i].num * v[i].len);
cout << ans << "\n";
}
};
using namespace solver;
signed main() {
ios::sync_with_stdio(false), cin.tie(0);
string s; cin >> s;
init_(s.size(), s);
solve();
return 0;
}
