program OOPtest;

{$APPTYPE CONSOLE}

uses
  SysUtils;
type
  testclass = class (TObject)
    procedure kill(a:integer); virtual; abstract;
  end;

  testdaughter = class (Testclass)
    procedure kill(a:integer); overload;
  end;

  testson = class (Testclass)
    procedure kill(a:integer); overload;
  end;

  procedure testson.kill(a:integer);
  begin
    write(a-1);
  end;

  procedure testdaughter.kill(a:integer);
  begin
    write(a+1);
  end;

var arr : array [1..2] of testclass;
var a : integer;
var s : testson;
var d : testdaughter;
begin
  a:=2;
  arr[1]:=s;
  arr[1]:=testson.Create;
  arr[1].kill(a);
  readln;
end.