#include <iostream>
using namespace std;
typedef long long ll;
const ll P=31;
const ll MOD=1000000007;
ll n;
string s;
ll inc[100001][27];
ll decr[100001];
ll add[100001];
ll hs[100005];
ll hs2[100005];
ll ans=0;
ll best=0;
ll powp[100005];
void bd()
{
ll i;
for(i=1;i<=n;i++)
hs[i]=(hs[i-1]+(s[i-1]-'a'+1)*powp[i-1])%MOD;
for(i=n;i>=1;i--)
hs2[i]=(hs2[i+1]+(s[i-1]-'a'+1)*powp[n-i])%MOD;
}
ll get(ll x, ll y, ll wch)
{
if(wch==1)
return ((hs[y]-hs[x-1]+MOD)*powp[n-y])%MOD;
else
return ((hs2[x]-hs2[y+1]+MOD)*powp[x-1])%MOD;
}
ll ok(ll x, ll aa, ll bb)
{
if(aa-x<=0 || bb+x>n || get(aa-x, aa, 1)!=get(bb, bb+x, 2))
return 0;
return 1;
}
void wk2(int aa, int bb)
{
ll lo=0, hi=n+1, m;
while(lo<hi){
m=(lo+hi)/2;
if(ok(m, aa, bb))
lo=m+1;
else
hi=m;
}
lo--;
ans+=lo+1;
if(aa==bb)
decr[aa]-=lo+1;
if(lo>=0){
if(aa==bb)
add[aa-lo]++, add[bb+1]-=2, add[bb+lo+2]++;
else
add[aa-lo]++, add[bb]--, add[bb+1]--, add[bb+lo+2]++;
}
if(aa-lo-1<=0 || bb+lo+1>=n+1)
return;
ll kp=lo;
lo=0, hi=n+1;
while(lo<hi){
m=(lo+hi)/2;
if(ok(m, aa-kp-2, bb+kp+2))
lo=m+1;
else
hi=m;
}
inc[aa-kp-1][s[bb+kp]-'a'+1]+=lo+1;
inc[bb+kp+1][s[aa-kp-2]-'a'+1]+=lo+1;
}
void ini()
{
ll i;
powp[0]=1;
for(i=1;i<=100004;i++)
powp[i]=powp[i-1]*P, powp[i]%=MOD;
}
void wk()
{
ll i;
ini();
bd();
for(i=1;i<=n;i++){
wk2(i, i);
if(i!=n)
wk2(i, i+1);
}
ll add2=0;
for(i=1;i<=n;i++)
add2+=add[i], add[i]=add2;
add2=0;
for(i=1;i<=n;i++)
add2+=add[i], decr[i]+=add2;
}
int main()
{
ios_base:: sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll i, j;
cin >> s, n=s.length();
wk();
for(i=0;i<n;i++){
ll f=s[i]-'a'+1;
for(j=1;j<=26;j++){
if(j==f)
continue;
best=max(best, inc[i+1][j]-decr[i+1]);
}
}
cout << ans+best << endl;
return 0;
}
