module Fibonacci: sig .. end
sig
end
The 0-th and 1-st Fibonacci numbers F_0 and F_1 are 1, and then F_n+2 = F_n + F_n+1.
F_0
F_1
F_n+2 = F_n + F_n+1
val calc : int -> Num.num
int -> Num.num
val phi_string : int -> string
int -> string