using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(ReturnSubstringCount("1011"));

        Console.WriteLine(ReturnSubstringCount("1110111100000111110"));

    }

    public static int ReturnSubstringCount(String s){

        int aux = 0;

        int count = 0;

        for(int i = 0; i < s.Length; i++){

            if(s[i].Equals('1')){

                aux++;

            }

            if(aux > count){

                count = aux;    

            }

            if(s[i].Equals('0')){

                aux=0;

            }   

        }

        return count;

    }

}