fun a (x, y) {
  var a = x + y, b = x - y;
  (
   var f = fun () {
     write (x);
     write (y);
     write (a);
     write (b)
   };

   a := 100;
   b := 200;
   x := 800;
   y := 1000;
   
    f
  )
}

var x = read ();

a (5, 7) ()