How to ls certain range of number

I have a directory that contains fifty folders named F01, F02....,F05. I want to count the total file number in F25 ~ F48, however, the only way I know is ls -1d F2[5-9]/*|wc -l and then type ls -1d F[3-4][0-9]/*|wc -l, and sum them up. Apparently this is not the right approach and it also includes F49.

So, what's the elegant way to do ls in this kind of certain pattern?