(* zadatak pod a *)

fun velika(nil) = nil | velika(h::t) = if (ord(h)>=65 andalso ord(h)<=90) then [h]@velika(t) else velika(t);
fun mala nil = nil | mala(h::t) = if (ord(h)>=97 andalso ord(h)<=122) then [h]@mala(t) else mala(t);

fun konacna(nil,nil) = nil | konacna(h1::t1,h2::t2) = [h1]@[h2]@konacna(t1,t2);
fun f1 x = konacna(velika(explode x),mala(explode x));

(* zadatak pod b - slican zadatku februar 2009 *)

fun broj(nil,x)=0 | broj(h::t,x) = if h=x then 1+broj(t,x) else broj(t,x);
fun nova(nil)=nil | nova(h::t) = if (broj(t,h)>0) then nova(t) else [h]@nova(t);

fun konacna(l,nil)=nil | konacna(l,h::t)= if (broj(l,h)<3) then [h]@konacna(l,t) else konacna(l,t);
fun f2 x = konacna(x,nova(x));