Ryspekov's Fibonacci sequence formula SWIFT

//  Created by Timur Ryspekov on 2017-06-16.
//  Copyright © 2017 GR. All rights reserved.
//

import Foundation

func zn(x: Int) -> Int {
 var x=abs(x)

 x=x+4
 x=x/5
 x=Int(pow(2,Double(x)))%2
 return x

 }


 var b = Int(readLine()!)!-1;

 var x=1
 var n=2
 while(n<b){
 n=n+1
 var k=Int(Double(x)*(1+pow(5,0.5))/2);
 x=k+zn(x: (n%3))*(k%2)+(1-zn(x: (n%3)))*zn(x: (k%2));
 print(x);
 }
 print()
 n=n+1
 x=x-zn(x: b)
 print(x)