#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn=300010;
char s[maxn];
int n,len,l,sz,first[maxn],tot;
long long ans;
struct trees{int len,fail,t[30],num;}t[maxn];
struct edges{int v,from;}e[maxn*3];
void insert(int u,int v)
{tot++;e[tot].v=v;e[tot].from=first[u];first[u]=tot;}
int getfail(int x)
{
    while(s[len-t[x].len-1]!=s[len])x=t[x].fail;
    return x;
}
void tree_work()
{
    int x=s[++len]-‘a‘;
    l=getfail(l);
    if(!t[l].t[x])
    {
        sz++;
        t[sz].len=t[l].len+2;
        t[sz].num=1;
        t[sz].fail=t[getfail(t[l].fail)].t[x];//偏小
        insert(t[sz].fail,sz);
        t[l].t[x]=sz;
    }
    else
    {
        t[t[l].t[x]].num++;
    }
    l=t[l].t[x];
}
long long dfs(int x)
{
    long long sum=t[x].num;
    for(int i=first[x];i;i=e[i].from)
    {
        sum+=dfs(e[i].v);
    }
    ans=max(ans,1ll*t[x].len*sum);
    return sum;
}
int main()
{
    scanf("%s",s+1);
    n=strlen(s+1);
    sz=1;
    s[0]=-1;//
    t[0].len=0;t[1].len=-1;
    t[0].fail=t[1].fail=1;
    t[0].num=t[1].num=1;
    insert(1,0);
    len=l=ans=0;
    for(int i=1;i<=n;i++)tree_work();
    dfs(1);
    printf("%lld",ans);
    return 0;
}