///roadtoVOI2025
///enjoythejourney
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define ii pair<int,int>
#define mp make_pair
#define in(x) freopen(x,"r",stdin)
#define out(x) freopen(x,"w",stdout)
#define bit(x,i) ((x>>i)&1)
#define lc (id<<1)
#define rc ((id<<1)^1)
const int mod=1e9+7;
const int maxn=1e5+7;
string s;
int p[maxn];
int h[maxn];
int hn[maxn];
int mul(int a,int b)
{
return (1ll*a*b)%mod;
}
int add(int a,int b)
{
ll c=a+b;
if(c>=mod)c-=mod;
return c;
}
int sub(int a,int b)
{
ll c=a-b;
if(c<0)c+=mod;
return c;
}
int get(int l,int r)
{
return sub(h[r],mul(h[l-1],p[r-l+1]));
}
int getn(int l,int r)
{
return sub(hn[l],mul(hn[r+1],p[r-l+1]));
}
int get(int l,int r,pair<int,int>nw)
{
int pref=sub(h[r],mul(h[l-1],p[r-l+1]));
if(nw.fi>=l&&nw.fi<=r){
pref=sub(pref,mul(s[nw.fi]-'a',p[r-nw.fi]));
pref=add(pref,mul(nw.se,p[r-nw.fi]));
}
return pref;
}
int getn(int l,int r,pair<int,int>nw){
int pref=sub(hn[l],mul(hn[r+1],p[r-l+1]));
if(nw.fi>=l&&nw.fi<=r){
pref=sub(pref,mul(s[nw.fi]-'a',p[nw.fi-l]));
pref=add(pref,mul(nw.se,p[nw.fi-l]));
}
return pref;
}
bool ispal(int l,int r)
{
return (get(l,r)==getn(l,r));
}
bool ispalnw(int l,int r,pair<int,int>nw)
{
return get(l,r,nw)==getn(l,r,nw);
}
void inp()
{
cin>>s;
}
int tknp(int lo,int hi,function<bool(int)>check)
{
int res=-1;
while(lo<=hi){
int m=(lo+hi)/2;
if(check(m)){
res=m;
lo=m+1;
}
else hi=m-1;
}
return res;
}
int good[maxn][30];
vector<int>getval(int n,const vector<ii>&val)
{
vector<int>tmp;
tmp.resize(n+1);
for(ii pp:val){
tmp[pp.fi]++;
tmp[pp.se+1]--;
}
for(int i=1;i<tmp.size();i++){
tmp[i]+=tmp[i-1];
}
for(ii pp:val){
tmp[pp.se+1]-=pp.se+1-pp.fi;
}
for(int i=1;i<tmp.size();i++){
tmp[i]+=tmp[i-1];
}
tmp.pop_back();
return tmp;
}
void sol()
{
int n=s.size();
s=' '+s;
p[0]=1;
for(int i=1;i<=n;i++){
h[i]=add(mul(h[i-1],31),s[i]-'a');
p[i]=mul(p[i-1],31);
}
hn[n+1]=0;
for(int i=n;i>=1;i--){
hn[i]=add(mul(hn[i+1],31),s[i]-'a');
}
function<bool(int)>check;
vector<ii>removals1;
ll sum=0;
vector<ii>removals2;
vector<pair<int,int>>diff;
for(int i=1;i<=n;i++){
int most=min(i-1,n-i);
check=[&](int x){
return ispal(i-x,i+x);
};
int rawpal=tknp(0,most,check);
sum+=rawpal+1;
pair<int,int> nw={i+rawpal+1,s[i-rawpal-1]-'a'};
check=[&](int x){
return ispalnw(i-x,i+x,nw);
};
if(rawpal!=0){
removals1.push_back({i-rawpal-1,i-1-1});
removals2.push_back({i+1-1,i+rawpal-1});
}
int nwpal=tknp(rawpal+1,most,check);
if(nwpal!=-1){
diff.push_back({i-rawpal-1,s[i+rawpal+1]-'a'});
diff.push_back({i+rawpal+1,s[i-rawpal-1]-'a'});
good[i-rawpal-1][s[i+rawpal+1]-'a']+=nwpal-rawpal;
good[i+rawpal+1][s[i-rawpal-1]-'a']+=nwpal-rawpal;
}
if (i < n) {
most = min(i, n - i);
check = [&](int d) { return ispal(i - d + 1, i + d); };
int raw_pal = tknp(0, most, check);
sum += raw_pal;
if (raw_pal > 0) {
removals1.push_back({i - raw_pal+1-1, i-1});
removals2.push_back({i + 1-1, i + raw_pal-1});
}
pair<int, int> rep = {i + raw_pal + 1, s[i - raw_pal]-'a'};
check = [&](int d) { return ispalnw(i - d + 1, i + d, rep); };
int rep_pal = tknp(raw_pal + 1, most, check);
if (rep_pal != -1) {
good[rep.first][rep.second] += rep_pal - raw_pal;
good[i - raw_pal][s[i + raw_pal + 1]-'a'] += rep_pal - raw_pal;
}
}
}
ll res=0;
res=sum;
for(ii &tmp:removals1){
}
for(ii &tmp:removals2){
tmp={n-tmp.se-1,n-tmp.fi-1};
}
vector<int>bad1=getval(n,removals1);
vector<int>bad2=getval(n,removals2);
reverse(bad2.begin(),bad2.end());
for(auto [i,j]:diff){
res=max(res,sum-bad1[i-1]-bad2[i-1]+good[i][j]);
}
cout<<res;
}
signed main(void)
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
inp();
sol();
// you should actually read the stuff at the bottom
return 0;
}
/* stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
*/
