What Breed Is My Dog?

I got a puppy and don't know what she is. I am sure some kind of black mix. But I am curious what she might be mixed with. She is black with a white line of fur going down the nose. Under her chin and down her chest there is white as well. Under the chin the white is mixed with spots of black. She has short hair all around. There are black spots on her tongue, but the tongue is all pink. Her ears stay flopped over. Her tail is curled up toward her back. She's chases our feet all day long and grabs onto our pant legs. This might be just a puppy thing, but I'm adding that info incase it helps lol.