How Long Is The Effect Of The Ipill? If Someone

How long is the effect of the ipill? If someone has sex with someone and they take a pill instantly. And if they do have sex again after 5 days of taking the pill, would the pill be effective still or does the lady need another pill? And what if they did not have sex but just a few drops of pre-cum stuck on the vaginal hair, then, after 5 days of taking the pill, do you need it again?