Hi can anyone help with what seems a simple task that I can't fathom. I want
to count characters in rows if the row starts with a certain inital in the
first columb:

a x x x
b x x x x
c x x x x x
a x x x
b x
c x x x x x


So what is the total number of "x" in rows begining with "b"

I thought it would be simple but I cant work out can someone help at all,

thanks