Wormhole

using System;
using System.Linq;

namespace _03.Wormhole
{
    class Wormhole
    {
        static void Main()
        {
            int[] wormhole = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int len = wormhole.Length;

            int index = 0;
            int steps = 0;
            while (index != len)
            {
                int currentInteger = wormhole[index];
                if (currentInteger != 0)
                {
                    wormhole[index] = 0;
                    index = currentInteger;
                }
                index++;
                steps++;
            }
            Console.WriteLine(steps);
        }
    }
}