public class Program
{
    public static void Main()
    {
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        string str = Console.ReadLine() ?? string.Empty;

        //1000000007 元の数

        int count = 0;
        for (int i = 0; i < str.Length; i++)
        {
            if (str[i] == '0')
            {
                count++;
            }
        }
        
        //〇の数の差計算して出力
        if( 8 > count)
        {
            Console.WriteLine(8 - count);
        }
        else
        {
            Console.WriteLine(count - 8);
        }


    }
}