#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define s second
#define f first
using namespace std;
const int N = 100005;
int mod = 1000000007,PR = 31,n,h[N],p[N],add[N][30],dlt[N],Rp[N],Rh[N],a1[N],b1[N];
int st[N],Rst[N];
vector <int> en[N],Ren[N];
string s;
bool check(int l1,int r1,int l2,int r2){
long long val1 = h[r1];
if (l1) val1 -= h[l1 - 1];
val1 = (val1%mod+mod)%mod;
long long val2 = Rh[l2];
if (r2 < n - 1) val2 -= Rh[r2 + 1];
val2 = (val2%mod+mod)%mod;
return ((val1 * Rp[r2])%mod == (val2 * p[l1])%mod);
}
int get(int L,int R){
int res=0,l = 0,r = n;
while (l <= r){
int mid = (l + r)>>1;
if (L - mid + 1 >= 0 && R + mid - 1 < n && check(L - mid + 1,L,R,R + mid - 1))
res = mid, l = mid + 1;
else
r = mid - 1;
}
return res;
}
signed main (){
cin>>s;
n = s.size();
for (int i = 0; i < n; i++){
if (i == 0){
p[i] = 1;
h[i] = (s[i] - 'a' + 1)%mod;
}else{
p[i] = (p[i - 1] * PR)%mod;
h[i] = (h[i - 1] + (p[i] * (s[i] - 'a' + 1))%mod)%mod;
}
}
for (int i = n - 1; i >= 0; i--){
if (i == n - 1){
Rp[i] = 1;
Rh[i] = (s[i] - 'a' + 1)%mod;
}else{
Rp[i] = (Rp[i + 1] * PR)%mod;
Rh[i] = (Rh[i + 1] + (Rp[i] * (s[i] - 'a' + 1))%mod)%mod;
}
}
int base_ans = 0;
for (int i = 0; i < n; i++){
for (int j = i; j <= min(n - 1,i + 1); j++){
int len = get(i,j);
base_ans += len;
int l = i - len + 1,r = j + len - 1;
if (i != j){
if (i - len + 1 <= i){
st[i - len + 1]++;
en[i].pb(len);
}
if (j + len - 1 >= j){
Rst[j+len-1]++;
Ren[j].pb(len);
}
}else{
if (i - len + 1 <= i - 1){
st[i - len + 1]++;
en[i-1].pb(len - 1);
}
if (j + len - 1 >= i + 1){
Rst[j+len-1]++;
Ren[i+1].pb(len - 1);
}
}
if (l > 0 && r < n - 1){
l--,r++;
int val = get(l - 1,r + 1) + 1;
add[l][s[r] - 'a' + 1] += val;
add[r][s[l] - 'a' + 1] += val;
}
}
}
int sm=0,cnt=0;
for (int i = 0; i < n; i++){
cnt += st[i];
sm += cnt;
dlt[i] = -sm;
for (int x: en[i]){
cnt--;
sm -= x;
}
}
sm=0,cnt=0;
for (int i= n-1;i>=0;i--){
cnt += Rst[i];
sm += cnt;
dlt[i] += -sm;
for (int x: Ren[i]){
cnt--;
sm -= x;
}
}
int best_add=0,sum = 0;
for (int i = 0; i < n; i++){
for (int j = 1; j <= 26; j++){
if (j == s[i] - 'a' + 1) continue;
if (add[i][j] + dlt[i] > best_add)
best_add = add[i][j] + dlt[i];
}
}
cout<<best_add + base_ans;
}
