#include <iostream>
#include <string>
using namespace std;
pair<int,int> alpha[26];
int main(){
    freopen("NOIVONG.INP","r",stdin);
    freopen("NOIVONG.OUT","w",stdout);
    int max = 0;
    for (int i = 0; i < 26;++i) alpha[i] = {-1,-1};
    string s;getline(cin,s);
    for (int i = 0;i < s.size();++i){
        int num = (int)s[i] - 65;
        if (alpha[num].first == -1) alpha[num].first = i;
        if (i > alpha[num].second) alpha[num].second = i;
    }
    for (pair<int,int> x : alpha){
        if (x.first == -1) continue;
        if (x.second-x.first+1 > max) max = x.second-x.first+1;
    }
    cout<<max;

}