#include <stdio.h>
#define MAX 100

int maior_sequencia_zeros(char seq[]){
    int cont_zero = 0;
    int max_seq = 0;
    for(int i = 0; seq[i] != '\0'; i++){
        if(seq[i] == '0'){
            cont_zero += 1;    
        } else {
            cont_zero = 0;
        }

        if(cont_zero > max_seq){
            max_seq = cont_zero;
        }
    } return max_seq;
}

int main() {
    char seq[MAX];
    scanf("%s", seq);

    printf("%d", maior_sequencia_zeros(seq)); 
    return 0;
}