#include <bits/stdc++.h>
using namespace std;
#define in ({int x=0;int c=getchar(),n=0;for(;!isdigit(c);c=getchar()) n=(c=='-');for(;isdigit(c);c=getchar()) x=x*10+c-'0';n?-x:x;})
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r){return l+rng()%(r-l+1);}
#define fasty ios_base::sync_with_stdio(0),cin.tie(0);
#define forinc(a,b,c) for(int a=b,_c=c;a<=_c;++a)
#define fordec(a,b,c) for(int a=b,_c=c;a>=_c;--a)
#define forv(a,b) for(auto&a:b)
#define fi first
#define se second
#define pb push_back
#define ii pair<int,int>
#define mt make_tuple
#define all(a) a.begin(),a.end()
#define reset(f, x) memset(f, x, sizeof(f))
#define bit(x,i) ((x>>(i-1))&1)
#define on(x,i) (x|(1ll<<(i-1)))
#define off(x,i) (x&~(1<<(i-1)))
#define gg exit(0);
const int N=600010;
int n,gap;
long long ret;
int pos[N],sa[N],tmp[N],lcp[N],ln[N],g[N];
int f[22][N];
string s,ss;
int cmp(int i,int j){
if(pos[i]!=pos[j]) return pos[i]<pos[j];
i+=gap, j+=gap;
return i<=n && j<=n ? pos[i]<pos[j] : i>j;
}
int que(int i,int j){
int t=ln[j-i+1];
return min(f[t][i],f[t][j-(1<<t)+1]);
}
int calc(int l,int r){
int lf=pos[l],rt=pos[l];
int le=pos[l],ri=n,mi;
while(le<=ri){
mi=(le+ri)/2;
if(que(pos[l],mi-1)>=r-l+1) rt=mi, le=mi+1;
else ri=mi-1;
}
le=1,ri=pos[l];
while(le<=ri){
mi=(le+ri)/2;
if(que(mi,pos[l]-1)>=r-l+1) lf=mi, ri=mi-1;
else le=mi+1;
}
return (rt-lf+1);
}
int p[N],r[N];
main(){
#define task "palindrome"
//freopen(task".inp","r",stdin);
//freopen(task".out","w",stdout);
fasty;
cin>>s; n=s.size();
ss=s; s="$";
forinc(i,1,n) s+="#", s+=ss[i-1]; s+="#"; n=s.size()-1;
forinc(i,1,n) sa[i]=i, pos[i]=s[i];
for(gap=1;;gap+=gap){
sort(sa+1,sa+n+1,cmp);
forinc(i,1,n-1) tmp[i+1]=tmp[i]+cmp(sa[i],sa[i+1]);
forinc(i,1,n) pos[sa[i]]=tmp[i]+1;
if(tmp[n]==n-1) break;
}
for(int i=1,k=0;i<=n;++i){
for(int j=sa[pos[i]+1];s[i+k]==s[j+k];) k++;
lcp[pos[i]]=k;
if(k) k--;
}
forinc(i,1,n) f[0][i]=lcp[i];
forinc(j,1,20) forinc(i,1,n){
if(i+(1<<j)>n+1) continue;
f[j][i]=min(f[j-1][i],f[j-1][i+(1<<j-1)]);
}
int mx=0,id=0,i,j,k,x;
forinc(i,1,n){
if (mx>=i) g[i]=min(mx-i,g[2*id-i]);
else g[i]=0;
while(i-g[i]-1>=1&&i+g[i]+1<=n&&s[i+g[i]+1]==s[i-g[i]-1]) g[i]++;
if(i+g[i]>mx){
for (x=mx-i+2;x<=g[i];x+=2){
ret=max(ret,(long long)calc(i-x,i+x)*x);
}
mx=i+g[i];
id=i;
}
}
cout<<ret;
}
