#include <bits/stdc++.h>
using namespace std;
#define pb push_back
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
const int maxn = 1e5 + 7;
const int mod = 1e9 + 7;
const int ba = 1337;
ll n, uk, uksl, hp[maxn], hs[maxn], pw[maxn], ra[2 * maxn], st[maxn], sl[maxn];
string s;
vi bs[maxn];
int add(int a, int b){
a += b;
if (a >= mod) a-= mod;
return a;
}
int sub(int a, int b){
a -= b;
if (a < 0) a += mod;
return a;
}
int mul(int a, int b){
return (ll)a * b % mod;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> s;
n = s.size();
s = '$' + s;
pw[0] = 1;
for (int i = 1; i <= n; i++)
pw[i] = mul(pw[i - 1], ba);
for (int i = 1; i <= n; i++)
hp[i] = add(mul(hp[i - 1], ba), s[i] - 'a');
for (int i = n; i > 0; i--)
hs[i] = add(mul(hs[i + 1], ba), s[i] - 'a');
ll ans = 0;
for (int i = 2; i <= 2 * n; i++){
ll sr = (i - 1) / 2;
int l = 0, r = min(sr, n - (i - sr) + 1);
while(l < r){
int m = (l + r + 1) / 2;
int le = sr - m + 1;
int ri = i - le;
int h1 = sub(hp[ri], mul(pw[ri - le + 1], hp[le - 1]));
int h2 = sub(hs[le], mul(pw[ri - le + 1], hs[ri + 1]));
if (h1 == h2) l = m;
else r = m - 1;
}
ra[i] = l;
ans += l + 1 - (i & 1);
bs[sr - l].pb(i);
bs[i - sr + l].pb(i);
sl[sr - l]++;
st[sr + 1] -= l;
sl[sr]--;
st[i - sr] += l;
sl[i - sr]--;
sl[i - sr + l]++;
}
ll mxdod = 0;
uksl += sl[0];
uk += st[0];
for (int i = 1; i <= n; i++){
uk += st[i] + uksl;
uksl += sl[i];
for (int j = 0; j < 26; j++){
if (j == (s[i] - 'a')) continue;
ll dod = -uk;
for (int sm : bs[i]){
int dr = sm - i;
if ((s[dr] - 'a') != j) continue;
ll sr = (sm - 1) / 2;
int l = 0, r = min(sr, n - (sm - sr) + 1);
while(l < r){
int m = (l + r + 1) / 2;
int le = sr - m + 1;
int ri = sm - le;
int h1 = sub(hp[ri], mul(pw[ri - le + 1], hp[le - 1]));
int h2 = sub(hs[le], mul(pw[ri - le + 1], hs[ri + 1]));
if (le <= i && i <= ri){
h1 = add(h1, mul(pw[ri - i], j - (s[i] - 'a')));
h2 = add(h2, mul(pw[i - le], j - (s[i] - 'a')));
}
if (h1 == h2) l = m;
else r = m - 1;
}
dod += l - ra[sm];
}
mxdod = max(mxdod, dod);
}
}
cout << ans + mxdod << "\n";
return 0;
}
