Is there anything I can do to get a cell to show how many times the same data is entered.

Example
1 A
2 B
3 B
4 B
5 A
6 B
7 A
8 A

Can I get something that will return the following:
A = 3
B = 2

Because B has come up 3 times in sucession (2-4) while A has only come up twice in sucession (7-8).