#!/usr/local/bin/swift
extension Int {
  var fizz:String? { return self % 3 == 0 ? "Fizz" : nil }
  var buzz:String? { return self % 5 == 0 ? "Buzz" : nil }
  var fizzbuzz:String { return (self.fizz! + self.buzz!) ?? String(self) }
}
print(4.fizz)