Here's a pretty accurate translation of her S cup size. She says she's a size larger than this 75LL or R bra, which is listed as 34LL U.S. on the size chart on bratabase. A size larger would be a 34M, 15 sizes up from a D cup!
Also in the try-on video she muses that "even if I went up 3 or 4 sizes more I would probably still be able to fit this bra" due to the stretchiness of the cups. "If my cupsize went up, not my back. My back is kinda where it's at."
That's an NN or an O by conventional sizes...