#0043 - Нули

#include <iostream>
#include <fstream>
#include <cmath>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <math.h>
#include <string>
#include <stdio.h>
#include <string.h>
#include <string>
#include <stdlib.h>
#include <cmath>
#include <iomanip>
#include <queue>
#include <utility>
#include <vector>
#include <stack>
#include <list>
#include <iterator>
#include <cctype>
#include <exception>
#include <cstdlib>
#include <stdexcept>
#include <csignal>
#include <pthread.h>

using namespace std;

int main(int argc, const char * argv[]) {

    string number;
    int countZero=0;
    int maxZero=0;
    cin>>number;
    for(int i=0; i<number.length();i++){
        if (number[i] == '0'){
            countZero++;
        }
        if (countZero>maxZero){
            maxZero=countZero;
        }

        if (number[i]=='1'){
            countZero=0;

        }

    }
    cout<<maxZero<<endl;
        return 0;
    }