This depends on the person, as people have different needs and athletes need more calories then normal scholars. The average is about 1,600-2,100. But again it depends on the person, for example I can only eat about 1,500 calories a day, despite the fact I'm an athlete, my friend however can eat about 2,500. If this is for personal use I would recommend consulting a doctor or trusted adult before you go on a diet.
Hope this helps :)
The two upper parts of the heart are the atriums and the bottom are the ventricles.