Sisters Waltz dancing

It's a tradition in their family that the little sister(Ameria) has to dance the waltz with the big sister(Divione) after the former turns 18. That happened about a year ago, for the first time, since Ameria is 19 already, so regardless, they dance the waltz every night. They are dancing the famous Waltz No. 2. I'm pretty sure you've heard it. If not, look it up on Youtube so you say ''Yes, I've heard that somewhere.''