Excel illiterate: frequency for intervals

I am illiterate in excel, sorry if my question seems stupid:

I am dealing with intervals: A1 = max value of set interval; B1 = min value of set interval

A B
1 7051 6770
2 6654 6462
3 6459 6253
4 6684 6469
5 6439 6253
6 5720 5513
7 5838 5623

I am looking for a formula to calculate the frequency of intervals that fall within a 500-mark range; In effect, the same interval would count more than once:

The frequency in this case would be (if my calculations are right)
7500-7000: 1

7000-6500: 3

6500-6000: 4

6000-5500: 2



Thank you in advance for any suggestion!

xi