Buy a lens between to complement my Oly 12 f/2.0 and Pana 25 f/1.4

I own an EM-5 and those lenses oly 12 mm f/2.0 and pana 25 mm f/1.4. I will travel to Venice next April , and I'm thinking to buy an oly 17 mm f/1.8 to compliment my lens. Do you think is a good option between my 12 & 25 lenses? Any other sugestions?

Thanks

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Salut,
Miquel
miquelfotografia.blogspot.com