using System;

public class Program

{

    public static int MinFlipsString(string s)

    {

        int res = 0;

        int num = 0;

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

        {

            if (s[i] == '0')

                res = Math.Min(num, res + 1);

            else 

                num++;

        }

​

        return res;

    }

    public static void Main()

    {

        Console.WriteLine("UniLecs");

        // tests

        Console.WriteLine(MinFlipsString("00110").ToString()); // 1

        Console.WriteLine(MinFlipsString("010110").ToString()); // 2

        Console.WriteLine(MinFlipsString("00011000").ToString()); // 2

    }

}