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

namespace _05.Fibonacci_Numbers
{
    class Program
    {
        static void Main()
        {
            int n = int.Parse(Console.ReadLine());

            Console.WriteLine(Fibonacci(n));
        }

        public static int Fibonacci(int x)
        {
            if (x <= 1)
                return 1;
            return Fibonacci(x - 1) + Fibonacci(x - 2);
        }

    }
}
