program Example;
$APPTYPE CONSOLE}
uses SysUtils;
var number1,number2,sum:integer;
procedure Add(n1,n2:integer; var sm:integer);
begin
 sm:=n1+n2;
end;
begin
 number1:=2; { We first initialize all variables }
 number2:=3;
 sum:=0;
 Add(number1,number2,sum);
end.