type
  Point = 
    record
      x : real;
      y : real;
    end;

function slope(p1, p2 : Point) : real;
  begin
    slope := (p2.y - p1.y) / (p2.x - p1.x)
  end;

procedure readPoint(var p : Point);
  begin
    writeln('enter a point');
    readln(p.x);
    readln(p.y)
  end;

var
  p1 : Point;
  p2 : Point;

begin
  readPoint(p1);
  readPoint(p2);
  writeln('the slope is ',slope(p1,p2))
end.