how to group categories with the same name in a graph?

I'm trying to make a fairly simple graph, but I just can't find out how.

I have a list of donations, let's say

person amount
mary 10
john 20
carl 15
rose 30
mary 10
carl 5
john 35
rose 10
mary 20
carl 10

so I want a pie chart showing how much each person donated, but it creates a chart with 3 different marys, 2 different johns, etc.

how can I make it to group data from fields with the same name?

Have you tried a PivotChart? (Attached)

Select the data, click insert-->PivotChart, and then build your chart.

No, I didn't actually know that you were supposed to do this with Pivot Charts. but that worked pretty well, thank you!