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

namespace Wormhole
{
    public class Wormhole
    {
        public static void Main()
        {
            var input = Console.ReadLine();
            var wormholes = input
                .Split(new[] { ' '}, StringSplitOptions.RemoveEmptyEntries)
                .Select(int.Parse)
                .ToArray();

            var counter = 0;

            for (int i = 0; i < wormholes.Length; i++)
            {
                if (wormholes[i] == 0)
                {
                    counter++;
                }
                else
                {
                    var realI = i;
                    i = (wormholes[i]-1);
                    wormholes[realI] = 0;
                   // counter++;

                }
            }

            Console.WriteLine(counter);

        }
    }
}