#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;
const int INF = 1e9 + 239;
namespace Hash {
int n;
string s;
int req(int i, int j, int len) {
while (len) {
if (i < 0 || j >= n) return 0;
if (s[i] != s[j]) return 0;
i--;
j++;
len--;
}
return 1;
}
void init(string s_) {
s = s_;
n = (int)s.size();
}
}
namespace SuffixArray {
int n;
string s;
vector<int> sa;
vector<int> wr;
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();
for (int i = 0; i < n; i++) {
sa.push_back(i);
}
sort(sa.begin(), sa.end(), [&](int i, int j) {
return cmp(i, j) == -1;
});
wr.resize(n);
for (int i = 0; i < n; i++) {
wr[sa[i]] = i;
}
}
}
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);
int ans = 0;
//even
{
vector<pair<int, int>> ip;
for (int i = 0; i < n; i++) {
int mx = -1;
//TODO
for (int j = 0; j <= i && i + j <= n; j++) {
if (Hash::req(i - 1, i, j)) {
mx = j;
}
}
ans = max(ans, 2 * mx);
if (mx != -1) {
ip.push_back({i, mx});
}
}
sort(ip.begin(), ip.end(), [&](pair<int, int> X, pair<int, int> Y) {
return SuffixArray::wr[X.first] < SuffixArray::wr[Y.first];
});
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)}));
}
int sz = (int)val.size();
for (int i = 0; i < sz; i++) {
int mn = INF;
for (int j = i; j < sz; j++) {
mn = min(mn, val[j]);
ans = max(ans, (j - i + 2) * (2 * mn));
}
}
}
//odd
{
vector<pair<int, int>> ip;
for (int i = 0; i < n; i++) {
int mx = -1;
//TODO
for (int j = 0; j <= i && i + j + 1 <= n; j++) {
if (Hash::req(i - 1, i + 1, j)) {
mx = j;
}
}
ans = max(ans, 2 * mx + 1);
if (mx != -1) {
ip.push_back({i, mx});
}
}
sort(ip.begin(), ip.end(), [&](pair<int, int> X, pair<int, int> Y) {
return SuffixArray::wr[X.first] < SuffixArray::wr[Y.first];
});
vector<int> val;
for (int i = 0; i + 1 < (int)ip.size(); i++) {
val.push_back(min({ip[i].second + 1, ip[i + 1].second + 1, SuffixArray::lcp(ip[i].first, ip[i + 1].first)}));
}
int sz = (int)val.size();
for (int i = 0; i < sz; i++) {
int mn = INF;
for (int j = i; j < sz; j++) {
mn = min(mn, val[j]);
ans = max(ans, (j - i + 2) * (2 * mn - 1));
}
}
}
cout << ans << endl;
}
