Now suppose once you fill the balloon up, there are no holes in the balloon. So the number of moles or number of molecules inside our balloon remains constant. Also, let's suppose that our pressure inside the store and outside is one ATM atmospheric pressure. So let's suppose that our pressure is also constant. Now, obviously, if it's winter, it's much colder outside than inside. So suppose I fill up my balloon with N number of moles of helium, and suppose now I go outside with that balloon.