I have data in this format: Agent and Line in Column A and Call numbers in Column B

Agent Calls
Jonathan Smith

Line 1 1
Line 2 6

Sarah Jones

Line 1 2
Line 2 4
Line 3 8


I am looking to get a formula that gives me the number of calls taken on line 1, line 2 etc for each agent. I have tried SUMPRODUCT but I think because my Line number and Agent are in the same column it returns an error. Any suggestions?