program triang;
var f :text;
    vx, vy :array[1..1500] of real;
    n,db :integer;

procedure beolvas;
var i:integer;
begin
  assign(f,'triang.in');reset(f);
     read(f,n);
     for i:=1 to n do read(f,vx[i],vy[i]);
  close(f);
end;

BEGIN
  db:=0;
  for i:=1 to n do
      for j:=1 to n do
          for k:=1 to n do
              if abs(vx[i]-vy[j])<0.0001 and abs(vx[j]-vy[k])-0.0001 then inc(db);
END.