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: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;
											b[k].x:=oX;
											b[k].y:=oY;
											end;
		end;
repeat
	ok:=true;
	for i:=1 to k-1 do
		if b[i].x*b[i+1].y>b[i].y*b[i+1].x 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-1 do
	begin
	 if b[i].x*b[i+1].y=b[i].y*b[i+1].x then
				while b[i].x*b[i+1].y=b[i].y*b[i+1].x  do
					begin
					j:=j+1;
					i:=i+1;
					end;
		 if j>1 then trap:=(j*(j-1)) div 2;
		i:=i+1;
		j:=1;
	end;
write(g,trap);
close(f);
close(g);
end.