I need help figuring out a formula to add duplicates as follows:

I have 3 months of figures with duplicate names on each month. I need to
add these amounts to a quarterly sheet. I want the names on the quarterly
sheet to show once, and with the totals for the 3 months. I'm hoping to not
also have to use a formula indicating a name in there, if that makes sense:

i.e
January;

Janet 5
Carol 10

February:
Bill 4
Janet 8

March:
Jon 11
Carol 14

Quarterly:
Janet 13
Carol 24
Bill 4
Jon 11