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?