/// In The Name Of God
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
#define pp pop_back
#define mp make_pair
#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()
#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define nl '\n'
#define ioi exit(0);
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
const int N = (int)3e5 + 7;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;
const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
using namespace std;
int n;
int p[N];
char s[N];
ll ans;
bool check(int l, int r) {
int cnt = 0;
while (l < r && ++cnt <= 200) {
if (s[l] != s[r]) return 0;
l++, r--;
}
int mid = l + r >> 1;
for (int i = mid; i >= l; i--) {
if (s[i] != s[r - i + mid]) return 0;
}
return 1;
}
ll get(int len) {
int mx = 0;
unordered_map <int, int> cnt;
for (int i = len; i <= n; i++) {
int mask = p[i] ^ p[i - len];
if (__builtin_popcount(mask) > 1) continue;
if (!check(i - len + 1, i)) continue;
mx = max(mx, ++cnt[mask]);
}
return (ll)mx * len;
}
int main() {
#ifdef IOI2018
freopen ("in.txt", "r", stdin);
freopen ("slow.out", "w", stdout);
#endif
Kazakhstan
cin >> (s + 1);
n = strlen(s + 1);
for (int i = 1; i <= n; i++) {
p[i] = p[i - 1] ^ (1 << (s[i] - 'a'));
}
for (int i = 1; i <= n && clock() / (double)CLOCKS_PER_SEC < 0.9; i++) {
ans = max(ans, get(i));
}
cout << ans;
ioi
}
