Is there a way to make excel tally for me?

The problem is as follows. I am given a long list of handwritten items with a quantity next to them. For context this relates to the number of lab supplies taken form a store room.

I then have to go down the list and input into excel how many of each item have been taken. The problem is that the items repeat. So somebody might have taken medium gloves and then something else. Then the next person might come in and take medium gloves. They don't add it up for me so i get given a long list of items.

E.g.
Gloves M - 27
Pipettes - 30
Scalpel - 50
Gloves M - 10

What i am doing at the moment is just quickly do the addition in my head as i add the info to excel. So if there was 27 taken before and now another 10 i change it to 37. i would like to be able to just input the 10 and then excel would automatically add it to the previous number to get to 37.

I hope that is clear enough.

looking forward to your feedback.

Matthew