program Trinagle;
uses
	Crt, Graph;
const
	eps = 0.00001; {Погрешность}
   numP = 4;
   numT = 4;
type
	tPoint = record
      x, y: real;
   end;
   tTriangle = record
   	a, b, c: tPoint;
   end;
var
   Points	    : array[1..numP] of tPoint;
   Triangles    : array[1..numT] of integer;
   table   	    : array[1..numT] of tTriangle;
   inF	  	    : text;
   i, j, k   	 : integer;
   p, p1, p2, p3: tPoint;
   c, s, d: integer;
   GrDriver, GrMode, GrError : integer;
   equal: Boolean;

procedure OpenFile(var f:text);
var
	Name: string;
   Err: integer;
begin
   repeat
    	WriteLn('Введите имя файла...');
    	ReadLn(name);
      Assign(f, Name);
      {$i-} Reset(f); {$i+}
      Err:= IOResult;
      if Err <> 0 then
      	writeln('Файл не найден...');
   until Err = 0;
   writeln('Файл открыт успешно...')
end;

procedure InputDots(var f: text);
var
   i: integer;
begin
   for i:= 1 to numP do
		ReadLn(f, points[i].x, points[i].y)
end;

function EqPoints(a, b: tPoint): Boolean; {Равенство двух точек}
begin
	EqPoints:= (abs(a.x - b.x) < eps) and (abs(a.y - b.y) < eps)
end;

function Includ(var a, b, c: tPoint): Boolean; {Проверка принадлежности}
var                                            		 {точки отрезку}
   p: real;
begin
   if ((b.x - c.x) < 0) and (not EqPoints(c, b)) then
	   p:= (a.x - c.x)/(b.x - c.x)
   else
		p:= 1 + 1;
   Includ:= (0 <= p) and
				(p <= 1) and
				(abs((p*b.y + (1 - p)*c.y) - a.y) < eps)
end;

procedure DrawDots;
var
   i  : integer;
	num: string;
begin
   for i:= 1 to numP do begin
		Circle(Round(points[i].x), Round(points[i].y), 2);
      Str(i, Num);
		OutTextXY(Round(points[i].x) + 4, Round(points[i].y) + 3, Num)
	end;
end;

procedure DrawTri(a, b, c: tPoint);
begin
   Line(round(a.x), round(a.y), round(b.x), round(b.y));
   Line(round(b.x), round(b.y), round(c.x), round(c.y));
   Line(round(c.x), round(c.y), round(a.x), round(a.y))
end;

procedure FindMaxTri(var mass: array of integer);
var
	max: integer;
begin
	max:= mass[1];
   for i:= 1 to k do
    	if mass[i] > max then
      	max:= i;
   DrawTri(table[i].a, table[i].b, table[i].c);
end;


begin
   OpenFile(inF); {Открытие файла}
   InputDots(inF);
   s:= 0;
   {Построение множества всех треугольников}
      for i:= 1 to numP do
		   for j:= 1 to numP do
            for k:= 1 to numP do begin
               p1.x:= points[i].x;
               p1.y:= points[i].y;
               p2.x:= points[j].x;
               p2.y:= points[j].y;
               p3.x:= points[k].x;
               p3.y:= points[k].y;
               c:= 0;
               for d:= 1 to numP do begin
                     p:= points[d];
                  equal:= (d = i) or (d = j) or (d = k);
                  if not equal then  begin
							table[s].a:= p1;
               		table[s].b:= p2;
               		table[s].c:= p3;
                     if Includ(p, p1, p2) or
								Includ(p, p1, p3) or
                     	Includ(p, p2, p3) then
									c:= c + 1
                   end;
               end;
               s:= s + 1;
               triangles[s]:= c
            end;
   {Инициализация графики}
      GrDriver:= Detect;
      InitGraph(GrDriver, GrMode, 'C:\TP\BGI');
      GrError:= GraphResult;
      if GrError <> GrOk then begin
		   WriteLn('Ошибка инициализации графики');
		   Halt
	   end;
   {Рисование}
      DrawDots; {Рисование точек}
      ReadLn;
      FindMaxTri(triangles);
      ReadLn;
      CloseGraph
end.