[{/**_id:573a1390f*/plot:"A greedy tycoon decides, on a whim, to corner the world market in whea…",genres:["Short","Drama"],countries:["México","USA"]},{/**_id:573a1390f*/plot:"A woman, with the aid of her police officer sweetheart, endeavors to u…",genres:["Drama"],countries:["México","USA","Canada"]}]

db.collection.aggregate([{$unwind:{path:"$genres"}},{$unwind:{path:"$countries"}},{$group:{_id:{pais:"$countries",genero:"$genres"},Total:{$sum:1}}},{$project:{_id:0,pais:"$_id.pais",genero:"$_id.genero",Total:1}}])