#include <iostream>
#include <fstream>
using namespace std;
int result;

int fib(int num)
{
  	if(num == 0)
	{
		return 0;
	}

	if(num == 1)
	{
		return 1;
	}

	result = fib(num - 1) + fib(num - 2);
	return result;
}

int main()
{
  ifstream read;
  read.open("kfib.in");
  int n;
  read >> n;
  read.close();
  fib(n);
  int k;
  k = result;
  ofstream write;
  write.open("kfib.out");
  write << k;
  write.close();
  return 0;
}