Find Cells That Contain Specific Text, Then Add Numbers In Adjacent Column

I have data in the following format. Double line break signifies a new column.

Text String || Number
c2-ag-1 || 3
c43-ag-4 || 2
c55-ag-1 || 5
c2-ag-3 || 1
c55-ag-2 || 4

How would I write a formula that outputs the following.

If contains:

c2 || 4
c43 || 2
c55 || 9