program fourrr;

var    a, b : real; { borders }
       h : real; { increment argument }
       s : real; { approximate value of the integral }
       n : integer; { number of intervals }
       x : real; { argument }
       y : real; { function value at the beginning of interval }
       i : integer;
begin

    write('lower border a: '); read(a);
    write('upper border b: '); read(b);
    write('increment argument h: '); read(h);

     n := (b - a) / (h + 1);
     x := a;
     s := 0;

    i := 1;
    while i <= n do
      begin
        y := x * x + 2;   // function value at the beginning of interval
        s := s + (y * h);
        x := x + h;
      end;

   writeln('Integral value: ', s);
end.