#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
using ull = unsigned long long;
const int N = 1e5 + 5, B = 311;
int n;
int cnt[N];
long long f[N];
array<long long, 26> c[N];
string s;
ull h[N], rh[N], pw[N];
ull qry(int l, int r, ull *h) {
return h[r] - h[l - 1] * pw[r - l + 1];
}
int find(int s, int e) {
if (s < 1 || e > n) {
return 0;
}
int l = 0, r = min(s, n - e + 1), res = 0;
while (l <= r) {
int m = (l + r) / 2;
if (qry(s - m + 1, s, h) == qry(n - e - m + 2, n - e + 1, rh)) {
res = m;
l = m + 1;
} else {
r = m - 1;
}
}
return res;
}
template<class T>
void upd(int s, int e, int x, T *f) {
f[s] += x;
f[e + 1] -= x;
}
signed main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> s;
n = s.size();
pw[0] = 1;
for (int i = 0; i < n; ++i) {
pw[i + 1] = pw[i] * B;
h[i + 1] = h[i] * B + s[i] - 'a' + 1;
}
for (int i = n - 1; i >= 0; --i) {
rh[i + 1] = rh[i + 2] * B + s[i] - 'a' + 1;
}
reverse(rh + 1, rh + n + 1);
long long res = 0;
for (int i = 1; i < n; ++i) {
int l = find(i, i + 1);
res += l;
int L = i - l + 1, R = i + l;
if (l > 0) {
upd(i + 1, i + l, 1, cnt);
upd(i + 1, i + l, -R - 1, f);
upd(i - l + 1, i, -1, cnt);
upd(i - l + 1, i, L - 1, f);
}
if (1 < L && R < n) {
int l = find(L - 2, R + 2);
c[L - 1][s[R] - 'a'] += l + 1;
c[R + 1][s[L - 2] - 'a'] += l + 1;
}
}
for (int i = 1; i <= n; ++i) {
int l = find(i - 1, i + 1) + 1;
res += l;
int L = i - l + 1, R = i + l - 1;
if (l > 1) {
upd(L, i - 1, -1, cnt);
upd(L, i - 1, L - 1, f);
upd(i + 1, R, 1, cnt);
upd(i + 1, R, -R - 1, f);
}
if (1 < L && R < n) {
int l = find(L - 2, R + 2);
c[L - 1][s[R] - 'a'] += l + 1;
c[R + 1][s[L - 2] - 'a'] += l + 1;
}
}
long long ma = 0;
for (int i = 1; i <= n; ++i) {
cnt[i] += cnt[i - 1];
f[i] += f[i - 1];
long long delta = (long long) cnt[i] * i + f[i];
for (int j = 0; j < 26; ++j) {
ma = max(ma, delta + c[i][j]);
}
}
cout << res + ma;
return 0;
}
