var n;

fun hd (l) {
  case l of
    h : _ ->  h
  esac  
}


fun tl (l) {
  case l of
    _ : tl ->  tl
  esac
}

fun print_list (l) {
  case l of
    {}    -> skip
  | h : t -> write (h); print_list (t)
  esac
}

n := read ();
write ({1, 2, 3}.hd);
print_list ({1, 2, 3}.tl)