#include<cstdio>
#include<cstring>
typedef long long ll;
const int maxn=1000005;
char str[maxn];
int next[maxn];
void getnext(){
    int j=0;
    next[0]=next[1]=0;
    for(int i=1;str[i]!='\0';++i){
        while(j!=0&&str[i]!=str[j])j=next[j];
        if(str[i]==str[j])j++;
        next[i+1]=j;
    }
}
struct edge{
    int to,next;ll w;
}lst[maxn<<1];int len=1;
int first[maxn];
void addedge(int a,int b,ll w){//printf("%d %d %lld\n",a,b,w);
    lst[len].to=b;
    lst[len].next=first[a];
    lst[len].w=w;
    first[a]=len++;
}
int T;
int q[maxn],head,tail;
int vis[maxn];ll dis[maxn];
int n;
int bfs1(){
    vis[0]=++T;
    head=tail=0;
    q[tail++]=0;
    dis[0]=0;
    while(head!=tail){
        int x=q[head++];
        for(int pt=first[x];pt;pt=lst[pt].next){
            if(vis[lst[pt].to]==T)continue;
            vis[lst[pt].to]=T;
            q[tail++]=lst[pt].to;
            dis[lst[pt].to]=dis[x]+lst[pt].w;
        }
        
    }
    int ans=0;
    for(int i=1;i<=n;++i){
        if(dis[i]>dis[ans])ans=i;
    }
    return ans;
}
ll bfs2(int s){
    vis[s]=++T;
    head=tail=0;
    q[tail++]=s;
    dis[s]=0;
    while(head!=tail){
        int x=q[head++];
        for(int pt=first[x];pt;pt=lst[pt].next){
            if(vis[lst[pt].to]==T)continue;
            vis[lst[pt].to]=T;
            q[tail++]=lst[pt].to;
            dis[lst[pt].to]=dis[x]+lst[pt].w;
        }
        
    }
    ll ans=0;
    for(int i=0;i<=n;++i){
        if(dis[i]>ans)ans=dis[i];
    }
    return ans;
}

int main(){
    freopen("savemzx.in","r",stdin);
    freopen("savemzx.out","w",stdout);
    scanf("%s",str);n=strlen(str);
    getnext();
    for(int i=1;i<=n;++i){
        addedge(next[i],i,(i-next[i])*1LL*(i-next[i]));addedge(i,next[i],(i-next[i])*1LL*(i-next[i]));
    }
    int u=bfs1();
    ll ans=bfs2(u);
    printf("%lld\n",ans);
    fclose(stdin);fclose(stdout);
    return 0;
}