Spreadsheet formula to count consecutive values in a column

Question

I have a column with "Y" and "N" values, and need a formula to count the last consecutive occurrences of "Y". So if I the column looks like this:

Y
Y
Y
N
Y
N
Y
Y

the desired result would be 2

Y
Y
Y
Y
N
N
Y

and here it would be 1

Y
Y
Y
Y
N

and here it would be 0. Is this possible with things like Excel, Numbers or Google Docs?