text: #include <iostream>
  
  using namespace std;
  
  int fibo(int n){
  	if(n == 1)
  		return 1;
  	if(n == 0)
  		return 0;
  	return fibo(n - 1) + fibo(n - 2);
  }
  
  int main(){
  	
  	//0 1 1 2 3 5 8 13
  	
  	int n;
  	
  	cin >> n;
  	
  	cout << fibo(n) << endl;
  	
  	return 0;
  }