// #pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define now chrono::steady_clock::now().time_since_epoch().count()
#define speedup cin.tie(0)->sync_with_stdio(0)
#define bitcount(x) __builtin_popcountll(x)
#define lla(x) x.rbegin(), x.rend()
#define all(x) x.begin(), x.end()
#define Tp template <class T>
#define int long long
#define pb push_back
#define vc vector
#define arr array
const int inf = 1e18;
struct HSH {
int b, mod;
vc<int> p, pf, sf;
HSH (string &s, int n, int _b = 39, int _mod = 1e9 + 7) : b(_b), mod(_mod) {
pf.assign(n + 2, 0);
sf.assign(n + 2, 0);
p.assign(n + 2, 1);
s = ' ' + s;
for (int i = 1; i <= n; i++) {
p[i] = (p[i - 1] * b) % mod;
pf[i] = (pf[i - 1] * b + (s[i] - 'a' + 1)) % mod;
} for (int i = n; i >= 1; i--) sf[i] = (sf[i + 1] * b + (s[i] - 'a' + 1)) % mod;
};
int getp (int l, int r) {
return (pf[r] - (pf[l - 1] * p[r - l + 1] % mod) + mod) % mod;
}
int gets (int l, int r) {
return (sf[l] - (sf[r + 1] * p[r - l + 1] % mod) + mod) % mod;
}
};
inline void solve () {
int n; string s;
cin >> s; n = s.size();
HSH h (s, n, 39, 1e9 + 7);
auto bs = [&] (int &m1, int &m2) -> void {
int l = 0, r = n - m2 + 1;
while (r - l > 1) {
int mid = (l + r) >> 1;
if (m1 - mid < 1 || h.getp(m2, m2 + mid) != h.gets(m1 - mid, m1)) r = mid;
else l = mid;
}
m2 += l;
m1 -= l;
};
int ans = 0;
unordered_map<int, int> dp;
for (int i = 2; i < n; i++) {
int l = i - 1, r = i + 1;
if (s[l] == s[r] ) {
bs(l, r);
while (l < r) {
int hash = h.getp(l, r);
// cout << l << ' ' << r << ' ' << hash << '\n';
dp[hash] += (r - l + 1);
l++; r--;
}
}
} for (int i = 1; i < n; i++) {
int l = i, r = i + 1;
if (s[l] == s[r]) {
bs(l, r);
while (l < r) {
int hash = h.getp(l, r);
// cout << l << ' ' << r << ' ' << hash << '\n';
dp[hash] += (r - l + 1);
l++; r--;
}
}
}
for (int i = 1; i <= n; i++) dp[h.getp(i, i)]++;
for (const auto &[x, val] : dp) ans = max(ans, val);
cout << ans << '\n';
}
signed main() {
speedup;
solve();
return 0;
}
// aa
