#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
mt19937 rng(69420);
bool check(int x) {
for (int i = 2; i * i <= x; ++i) {
if (x % i == 0) {
return 1;
}
}
return 0;
}
int prime(int s, int e) {
int x = rng() % (e - s + 1) + s;
while (!check(x)) {
--x;
}
return x;
}
using T = array<int, 3>;
const int N = 1e5 + 5;
T M = {prime(1e8, 1e9), prime(1e8, 1e9), prime(1e8, 1e9)}, B = {prime(1000, 10000), prime(1000, 10000), prime(1000, 10000)};
int n;
int cnt[N], h[3][N], rh[3][N], pw[3][N];
long long f[N];
array<long long, 26> c[N];
string s;
int qry(int l, int r, int *h, int M, int *pw) {
return ((h[r] - (long long) h[l - 1] * pw[r - l + 1]) % M + M) % M;
}
array<int, 3> qry(int l, int r, int h[3][N]) {
array<int, 3> res{};
for (int i = 0; i < 3; ++i) {
res[i] = qry(l, r, h[i], M[i], pw[i]);
}
return res;
}
int find(int s, int e) {
if (s < 1 || e > n) {
return 0;
}
int l = 1, 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();
for (int j = 0; j < 3; ++j) {
pw[j][0] = 1;
for (int i = 0; i < n; ++i) {
pw[j][i + 1] = (long long) pw[j][i] * B[j] % M[j];
h[j][i + 1] = ((long long) h[j][i] * B[j] + s[i] - 'a' + 1) % M[j];
}
}
for (int j = 0; j < 3; ++j) {
for (int i = n - 1; i >= 0; --i) {
rh[j][i + 1] = ((long long) rh[j][i + 2] * B[j] + s[i] - 'a' + 1) % M[j];
}
reverse(rh[j] + 1, rh[j] + 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;
}
