wormhole

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace wormholeizpit30april
{
    class Program
    {
        static void Main(string[] args)
        {

            int [] wormhole = Console.ReadLine().Split(new[]{' '},StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();

            // Console.WriteLine("input done");

            int count = 0;

            for(int i=0;i<wormhole.Length;i++)
            {
                if(wormhole[i]==0)
                {
                    count++;
                }
                else
                {
                    int temp = wormhole[i];
                    wormhole[i] = 0;
                    i = temp;
                    count++;
                }
           }

            Console.WriteLine(count);


        }
    }
}