Potential calculation error on WordPiece section

Hello, I was reading the [WordPiece section](https://huggingface.co/course/chapter6/6?fw=pt) and found the score calculation between `hu` and `##g` from the end of ***training algorithm*** part doesn't make sense to me. Specifically, the frequency of `hug` should be 10 while both `hu` and `##g` have a frequency of 15, which yields a score of 10/(15*15), and is not equal to 1/15, as shown on the website.