function avg (num1,num2 : integer) : real;
var
   small,big : integer;
begin
   if num1=num2 then
      avg := num1
   else
   begin
      if num1>num2 then
         big := num1
      else
         big := num2;
      small := num1 + num2 - big;
      if small+1=big then
         avg := small+0.5
      else
         avg := avg(small+1,big-1);
   end;
end;