here is a functional program to get you started...

init a counter

open the file and read it line by line

split each line on space to get an array of the fvalue and svalue

increment the counter if fvalue is within the range AND svalue is with
+in the range

close the file
[download]

It is really easy so I hope you will find it fun to convert the above into Perl.

Good luck.

update: You can even avoid the splitting in line 3 by using a simple regexp to get the fvalue and svalue. Might result in a possible speed increase, and will eliminate one spurious variable creation.