--  phi.adb

with Ada.Text_IO, Ada.Integer_Text_IO;
use Ada.Text_IO, Ada.Integer_Text_IO;

procedure phi is
   a : Integer;
   b : Integer;

   function phi_func (n, o : Integer) return Integer is
   begin
      if n = 0 then
         return (o + 1);
      elsif o = 0 then
         return (phi_func (n - 1, 1));
      else
         return (phi_func (n - 1, phi_func (n, o - 1)));
      end if;
   end phi_func;

begin
   Put ("Gib eine Zahl fuer a ein! a = ");
   Get (a);
   Put ("Gib eine Zahl fuer b ein! b = ");
   Get (b);

   Put (phi_func (a, b));
end phi;