program trapez;
type casuta=record
						x,y:int64;
						end;
		vector=array[1..1000000] of casuta;
var a:array[1..100000] of casuta;
		b:vector;
		n,i,j,k,trap,caz:int64;
		oX,oY:int64;
		f,g:text;
		aux:casuta;
		ok:boolean;
begin
assign(f,'trapez.in'); reset(f);
assign(g,'trapez.out'); rewrite(g);
read(f,n);
k:=0;
for i:=1 to n do
	read(f,a[i].x,a[i].y);
for i:=1 to n-1 do
	for j:=i+1 to n do
		begin
		oX:=a[i].x-a[j].x;
		oY:=a[i].y-a[j].y;
		if (oX<>0) then  begin
											k:=k+1;

											if oY<0 then  begin b[k].y:=-1*oY; b[k].x:=-1*oX; end else
												begin
												b[k].y:=oY;
												b[k].x:=oX;
												end;
											end;
		end;
repeat
	ok:=true;
	for i:=1 to k-1 do
		if b[i].y*b[i+1].x>b[i].x*b[i+1].y then
					begin
					aux:=b[i];
					b[i]:=b[i+1];
					b[i+1]:=aux;
					ok:=false;
					end;
until ok;

i:=1;
j:=1;
while i<k do
	begin
		if b[i].y*b[i+1].x=b[i].x*b[i+1].y then
			while (b[i].y*b[i+1].x=b[i].x*b[i+1].y) and (i<k) do
				begin
					j:=j+1;
					i:=i+1;
				end;
	if j<>1 then trap:=trap+(j*(j-1) div 2);
	j:=1;
	i:=i+1;
	end;

write(g,trap);
close(f);
close(g);
end.