I have a document with duplicates entries, and was wondering how I could combine duplicates

ie, I have:
Colom A, Colom b
bob, 10
lisa, 5
bob, 6
lisa, 2
mark, 4
mark, 1
bob, 2

I want:
Colom A, Colom b
bob, 18
lisa, 7
mark, 5

Any suggestions? Is there a built in tool?