3 formal (tuxedos) 3 or 4 semi formal (suites of blazers and ties) and the rest casual (slacks and polo shirts or similar).
Celebrity no longer do Semi formal. Its either Formal or Smart Casual. There will be 3 formal nights. The remainder are smart casual - for gents trousers with a shirt (long or short sleeved) no need for a jacket.
Just returned from the Baltic on Eclipse and we had 3 Formal nights and the rest were Smart Casual. No extra jacket required unless you want to eat in the Murano restaurant, where most men were wearing them. Hope this helps and have a great time on this lovely ship.