Live up to every day            */

#include<cstdio>

#include<cmath>

#include<iostream>

#include<algorithm>

#include<vector>

#include<stack>

#include<cstring>

#include<queue>

#include<set>

#include<string>

#include<map>

#include <time.h>

#define PI acos(-1)

using namespace std;

typedef long long ll;

typedef double db;

const int maxn = 1e6+;

const int sigma=;

const ll mod = ;

const int INF = 0x3f3f3f;

const db eps = 1e-;

struct ptree{

    char s[maxn];

    int next[maxn][sigma], fail[maxn], cnt[maxn], len[maxn];

    int last, n, p;

    ll res;

    inline int newnode(int l) {

        cnt[p]=;

        len[p]=l;

        return p++;

    }

    inline void init() {

        n=, p=, last=;

　　　　　　memset(next, 0, sizeof(next));
　　　　　　memset(cnt, 0, sizeof(cnt));
　　　　　　memset(len, 0, sizeof(len));
　　　　　　memset(fail, 0, sizeof(fail));

        newnode(), newnode(-);

        s[n]=-;

        fail[]=;

        //cout<<n<<" "<<p<<" "<<last<<endl;

    }

    inline int FL(int x) {

        while(s[n-len[x]-]!=s[n])  x=fail[x];

        return x;

    }

    void add(char c) {

        c-='a';

        s[++n]=c;

        int cur=FL(last);

        if (!next[cur][c]) {

            int now=newnode(len[cur]+);

            fail[now]=next[FL(fail[cur])][c];

            next[cur][c]=now;

        }

        last=next[cur][c];

        ++cnt[last];

    }

    inline ll countt() {

        ll pk=;

        for (int i=p-; ~i; --i) {

            cnt[fail[i]]+=cnt[i];

            pk=max(pk, (ll)cnt[i]*(ll)len[i]);

        }

        return pk;

    }

}p;

char s[maxn];

void solve(){

    scanf("%s",s);

    int len=strlen(s);

    p.init();

    for(int i=;i<len;i++)

        p.add(s[i]);

    printf("%lld\n",p.countt());

}

int main() {

    int t = ;

   // freopen("in.txt", "r", stdin);

    //freopen("out.txt", "w", stdout);

    //scanf("%d", &t);

    while(t--)

        solve();

    return ;

}