#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cassert>
#include <map>
using namespace std;
#define int long long
typedef pair<int, int> P;
#define rep(i, n) for (int i=0; i<(n); i++)
#define all(x) x.begin(), x.end()
#define uniq(x) x.erase(unique(all(x)), x.end())
#define index(x, y) (int)(lower_bound(all(x), y) - x.begin())
#define _1 first
#define _2 second
#define pb push_back
#define MOD 1000000007
const int B = 123;
string S;
int N;
map<int, int> C[300001];
int HL[3000][3000], HR[3000][3000];
signed main() {
cin >> S;
N = S.length();
rep(l, N) {
int h = 0;
for (int r=l; r<N; r++) HL[l][r] = h = (h*B+S[r])%MOD;
}
rep(r, N) {
int h = 0;
for (int l=r; l>=0; l--) HR[l][r] = h = (h*B+S[l])%MOD;
}
rep(r, N) rep(l, r+1) {
if (HL[l][r] == HR[l][r]) C[r-l+1][HL[l][r]]++;
}
long long m = 0;
for (int len=1; len<=N; len++) {
for (auto p : C[len]) {
m = max(m, 1LL*len*p._2);
}
}
cout << m << "\n";
return 0;
}
