Question: Valascia is an indoor sporting arena located in Ambrì, Switzerland, it is the home arena of the HC Ambri-Piotta ice hockey team, of which professional ice hockey league in Switzerland, it is the top tier of the Swiss hockey league system? 
Sentence (from "National League (ice hockey)"): It is the top tier of the Swiss hockey league system and of the two-tier National League.
Relevant evidence: No