Trying to write an arrayformula that will count each date once per student. Surprisingly difficult.

I have a spreadsheet that tracks homework.

In column F are dates, in column H are student names.

In column R the student names appear one time each. In column S I want to count how many days each student in column R did homework.

So if the John did homework once on 10/15/2023, three times on 10/20/2023, and twice on 10/21/2023, it will return a value of "3" next to John's name in column S.

chatGPT was absolutely useless in solving this. Any ideas?