Reset count on name change

Col A Col B

Bob 1
Bob 2
Bob 3
Bob 4
Bob 5
Bob 6
Bob 7
Bob 8
John 1
John 2
John 3
John 4
Joe 1
Joe 2
Joe 3
Joe 4
Joe 5
Joe 6
Joe 7


I want to get column B. Basically count sequentially until there is a name change, then restart the count. Any ideas?

Cell B1 = 1
Cell B2 to down =IF(A2=A1,B1+1,1)

Thanks, perfect.