test: procedure options (main, reorder);
   declare (n, i) fixed binary (31);

   get list (n);
   put edit ( n, '[' ) (x(1), a);
restart:
   if is_prime(n) then
      do;
         put edit (trim(n), ']' ) (x(1), a);
         stop;
      end;
   do i = n/2 to 2 by -1;
      if is_prime(i) then
         if (mod(n, i) = 0) then
            do;
               put edit ( trim(i) ) (x(1), a);
               n = n / i;
               go to restart;
            end;
   end;
   put edit ( ' ]' ) (a);

is_prime: procedure (n) options (reorder) returns (bit(1));
   declare n fixed binary (31);
   declare i fixed binary (31);

   if n < 2 then return ('0'b);
   if n = 2 then return ('1'b);
   if mod(n, 2) = 0 then return ('0'b);

   do i = 3 to sqrt(n) by 2;
      if mod(n, i) = 0 then return ('0'b);
   end;
   return ('1'b);
end is_prime;

end test;