#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <fstream>
#include <cassert>
#include <cstring>
#include <unordered_set>
#include <unordered_map>
#include <numeric>
#include <ctime>
#include <bitset>
#include <complex>
#include <chrono>
#include <random>
#include <functional>
using namespace std;
typedef long long ll;
const int ALP = 26;
namespace Hash {
const int MOD = 1e9 + 7;
const int BASE = 31;
int add(int a, int b) {
if (a + b < MOD) {
return a + b;
}
return a + b - MOD;
}
int sub(int a, int b) {
if (a >= b) {
return a - b;
}
return a - b + MOD;
}
int mul(int a, int b) {
return 1LL * a * b % MOD;
}
int n;
string s;
vector<int> pw;
vector<int> h;
vector<int> rh;
int req(int i, int j, int len) {
i = n - 1 - i;
int F = sub(rh[i + len], mul(rh[i], pw[len]));
int S = sub(h[j + len], mul(h[j], pw[len]));
return F == S;
}
void init(string s_) {
s = s_;
n = (int)s.size();
pw.resize(n + 1);
h.resize(n + 1);
rh.resize(n + 1);
pw[0] = 1;
for (int i = 0; i < n; i++) {
pw[i + 1] = mul(pw[i], BASE);
}
for (int i = 0; i < n; i++) {
h[i + 1] = add(s[i], mul(h[i], BASE));
}
reverse(s.begin(), s.end());
for (int i = 0; i < n; i++) {
rh[i + 1] = add(s[i], mul(rh[i], BASE));
}
reverse(s.begin(), s.end());
}
}
namespace SuffixArray {
int n;
string s;
vector<int> sa;
vector<int> wr;
vector<tuple<int, int, int>> tos;
void do_sort() {
sort(tos.begin(), tos.end());
}
void build_sa() {
s.push_back(0);
n++;
vector<int> cur_class(n);
{
vector<char> hv;
for (auto c : s) {
hv.push_back(c);
}
sort(hv.begin(), hv.end());
hv.resize(unique(hv.begin(), hv.end()) - hv.begin());
for (int i = 0; i < n; i++) {
cur_class[i] = lower_bound(hv.begin(), hv.end(), s[i]) - hv.begin();
}
}
for (int l = 1; l < n; l *= 2) {
for (int i = 0; i < n; i++) {
tos.push_back({cur_class[i], cur_class[(i + l) % n], i});
}
do_sort();
int cnt = 0;
for (int i = 0; i < n; i++) {
cur_class[get<2>(tos[i])] = cnt;
if (i > 0) {
cnt += (get<0>(tos[i]) != get<0>(tos[i - 1]) || get<1>(tos[i]) != get<1>(tos[i - 1]));
}
}
}
sa.resize(n);
for (int i = 0; i < n; i++) {
sa[i] = cur_class[i];
}
wr.resize(n);
sa.erase(sa.begin());
n--;
for (int i = 0; i < n; i++) {
wr[sa[i]] = i;
}
}
int lcp(int i, int j) {
//TODO
int ans = 0;
while (i < n && j < n) {
if (s[i] != s[j]) {
return ans;
}
ans++;
i++;
j++;
}
return ans;
}
int eq(int i, int j, int len) {
return lcp(i, j) >= len;
}
int cmp(int i, int j) {
int sk = lcp(i, j);
i += sk;
j += sk;
if (i == n && j == n) {
return 0;
}
if (i == n || s[i] < s[j]) {
return -1;
} else {
return 1;
}
}
void init(string s_) {
s = s_;
n = (int)s.size();
build_sa();
wr.resize(n);
for (int i = 0; i < n; i++) {
wr[sa[i]] = i;
}
}
}
void solve(vector<int> v, int ml, int add, ll &ans) {
int n = (int)v.size();
vector<int> l(n);
vector<int> r(n);
{
vector<int> st;
for (int i = 0; i < n; i++) {
while (!st.empty() && v[st.back()] >= v[i]) {
st.pop_back();
}
if (st.empty()) {
l[i] = -1;
} else {
l[i] = st.back();
}
st.push_back(i);
}
}
{
vector<int> st;
for (int i = n - 1; i >= 0; i--) {
while (!st.empty() && v[st.back()] >= v[i]) {
st.pop_back();
}
if (st.empty()) {
r[i] = n;
} else {
r[i] = st.back();
}
st.push_back(i);
}
}
for (int i = 0; i < n; i++) {
ans = max(ans, (ll)(r[i] - l[i]) * (v[i] * ml + add));
}
}
int cnt[ALP];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
string s;
cin >> s;
int n = (int)s.size();
Hash::init(s);
SuffixArray::init(s);
ll ans = 0;
auto cmp = [&](pair<int, int> X, pair<int, int> Y) {
int i1, len1, i2, len2;
tie(i1, len1) = X;
tie(i2, len2) = Y;
int sk = SuffixArray::lcp(i1, i2);
if (sk >= len1 || sk >= len2) {
return len1 < len2;
}
i1 += sk;
i2 += sk;
return (i1 == n || s[i1] < s[i2]);
};
//single
{
for (int i = 0; i < n; i++) {
cnt[s[i] - 'a']++;
ans = max(ans, (ll)cnt[s[i] - 'a']);
}
}
//even
{
vector<pair<int, int>> ip;
for (int i = 0; i < n; i++) {
int mx = -1;
int l = -1;
int r = n +1;
while (r - l > 1) {
int mid = (r + l) / 2;
if (mid <= i && mid + i <= n && Hash::req(i - 1, i, mid)) {
l = mid;
} else {
r = mid;
}
}
mx = l;
ans = max(ans, (ll)2 * mx);
if (mx != -1) {
ip.push_back({i, mx});
}
}
sort(ip.begin(), ip.end(), cmp);
vector<int> val;
for (int i = 0; i + 1 < (int)ip.size(); i++) {
val.push_back(min({ip[i].second, ip[i + 1].second, SuffixArray::lcp(ip[i].first, ip[i + 1].first)}));
}
solve(val, 2, 0, ans);
}
//odd
{
vector<pair<int, int>> ip;
for (int i = 0; i < n; i++) {
int mx = -1;
int l = -1;
int r = n +1;
while (r - l > 1) {
int mid = (r + l) / 2;
if (mid <= i && mid + i + 1 <= n && Hash::req(i - 1, i + 1, mid)) {
l = mid;
} else {
r = mid;
}
}
mx = l;
ans = max(ans, (ll)2 * mx + 1);
if (mx != -1) {
ip.push_back({i, mx + 1});
}
}
sort(ip.begin(), ip.end(), cmp);
vector<int> val;
for (int i = 0; i + 1 < (int)ip.size(); i++) {
val.push_back(min({ip[i].second, ip[i + 1].second, SuffixArray::lcp(ip[i].first, ip[i + 1].first)}));
}
solve(val, 2, -1, ans);
}
cout << ans << endl;
}
