#include <bits/stdc++.h>
using namespace std;
using ull = unsigned long long;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
string s;
cin >> s;
int n = (int)s.size();
const ull base = 911382323ull;
vector<ull> pw(n + 1), h1(n + 1), h2(n + 1);
pw[0] = 1;
for (int i = 1; i <= n; i++) pw[i] = pw[i - 1] * base;
for (int i = 1; i <= n; i++) {
h1[i] = h1[i - 1] * base + (s[i - 1] - 'a' + 1);
}
string t = s;
reverse(t.begin(), t.end());
for (int i = 1; i <= n; i++) {
h2[i] = h2[i - 1] * base + (t[i - 1] - 'a' + 1);
}
auto get1 = [&](int l, int r) -> ull {
return h1[r] - h1[l - 1] * pw[r - l + 1];
};
auto get2 = [&](int l, int r) -> ull {
return h2[r] - h2[l - 1] * pw[r - l + 1];
};
auto ispal = [&](int l, int r) -> bool {
int rl = n - r + 1;
int rr = n - l + 1;
return get1(l, r) == get2(rl, rr);
};
map<pair<ull,int>, int> mp;
for (int i = 1; i <= n; i++) {
for (int j = i; j <= n; j++) {
if (ispal(i, j)) {
mp[{get1(i, j), j - i + 1}]++;
}
}
}
long long ans = 0;
for (auto x : mp) {
ans = max(ans, 1LL * x.first.second * x.second);
}
cout << ans << '\n';
return 0;
}
