strings

#include <iostream>
#include <set>
#include <map>
#include <vector>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <cstdio>
#include <stack>
#include <iomanip>
#include <numeric>
#include <fstream>
#include <functional>
#include <sstream>

#define SSTR( x ) dynamic_cast< std::ostringstream & >( \
       ( std::ostringstream() << std::dec << x ) ).str()
#define LL long long
#define fr(i,j) for(int i=0; i<j; i++)
#define each(i,in,j) for(int i=in; i<j; i++)
#define F first
#define S second
using namespace std;

ifstream fin("strings.in");
#define cin fin

ofstream fout("strings.out");
#define cout fout

const int con = 1e9;
typedef vector<int> vi;
typedef vector<vector<int > > vvi;
typedef vector<pair<int,int > > vpi;
typedef pair<int, int> pi;
typedef vector<int>::iterator viit;
typedef vector<LL> vll;
typedef vector<bool> vb;
template <typename T>
void gv (vector<T>& a){
       fr(h,a.size()) scanf("%d",&a[h]);
}
void gv (vpi& a){
   int b,c;
   fr(h,a.size()) {
       scanf("%d %d",&b,&c);
       a[h].first = b;
       a[h].second = c;
   }
}
int max(int a, int b) {
    return a>b?a:b;
}
void pnt (vi a, int n) {
       fr(h,n) cout<<a[h]<<" ";
       cout<<"\n";
}
template <typename T>
void pnt (vector<T> a) {
       if (a.size()==0) cout<<"\n";
       fr(h,a.size()-1) cout<<a[h]<<" ";
       cout<<a.back()<<"\n";
}
void pnt (vvi a) {
       fr(h,a.size()) pnt(a[h]);
}
int gcd (int a, int b) {
        return b ? gcd (b, a % b) : a;
}
vpi v;

bool cond (int i, int j){
    pi p1 = v[i], p2 = v[j];
    return (p1.F<p2.F)||(p1.F==p2.F&&p1.S<=p2.S);
}
map<string, int> m;
vi oc;
int mx;
string ans;
string s;
int n;
void proc(int l){
    bool b;
    for(int i = 0; i <= n-l; i++){
        b = true;
        int lim = i+l;
        for(int j = i; j<i+l; j++){
            if (oc[j]<lim) b = false;
        }
        if (b) {
            string t = s.substr(i,l);
            m[t]++;
            if (m[t]>=mx) mx = m[t], ans = t;
        }
    }
}
int main()
{

    cin>>s;
    n = s.size();
    oc.resize(n, n+1);
    map<char, int> oc2;
    fr(i,n){
        if (oc2.find(s[i])!=oc2.end()) oc[oc2[s[i]]] = i;
        oc2[s[i]] = i;
    }
    oc2.clear();
    fr(i,n){
        oc2[s[i]]++;
        if (oc2[s[i]]>mx) {
            mx = oc2[s[i]];
            ans = s.substr(i,1);
        }
    }
    int l = 1;
    int r = 27;
    while(l<r-1){
        m.clear();
        int mid = l + (r-l)/2;
        string t = ans;
        proc(mid);
        if (t!=ans) l = mid;
        else r = mid;
    }
    cout<<ans.size()<<"\n";

    return 0;
}