using System;

public class Program

{

    public static void Main()

    {

        string ser = "1111111111111001111011111";

​

        int maxCount = FindMaxOccurence(ser);

        Console.WriteLine(maxCount);

    }

    static int FindMaxOccurence(string str)

    {

        int maxCount = 0;

        string newStr = string.Empty;

        int i =0;

        //foreach(char c in str){

        for(int j = 0;j < str.Length-1; j++){   

            if(str[j] == '1'){

                maxCount++;

            }

               i++;

        }

        return maxCount;

    }

}