{
    def f(x: Double, n: Int): Double = {
      if (n == 0) 1
      else if (n > 0 && n % 2 == 0) f(f(x, n/2), 2)
      else if (n > 0 && n % 2 != 0) x * f(x, n - 1)
      else (1 / f(x, -n))
    }
    println(f(4,3))
  }