What size snap ring is on the shaft that drives the raw water pump?

I removed my old oberdorfer to install a new N202M-908 and saw a snap ring hanging. So I reached in to see what it was doing in there and noticed too late it was broken. And it dropped inside the engine right under the shaft.

It seems to have been broken for a while so I think the smaller piece isn't going to be an issue. The remaining snap ring I working on trying to get out with a magnet or something.

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