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? 

full_context: Document 1: HC Davos: Hockey Club Davos is a professional Swiss ice hockey club based in Davos, Switzerland. Davos plays in the National League (NL). The team is usually a strong force in the league and often bolster their roster with Swiss national team players and players who once played for National Hockey League teams. HC Davos also has hosted the annual Spengler Cup tournament, an invitational competition, since 1923.
Document 2: List of pre-NHL seasons: Prior to the first season of the National Hockey League (NHL), which commenced on December 19, 1917, there had been many seasons of ice hockey played by various amateur and professional leagues, often held contemporaneously, going back to the 1880s, to which the NHL can trace its roots. Below is a list of pre-NHL seasons by ice hockey leagues that are precursors of the National Hockey League.
Document 3: DSC Indoor Arena: DSC Indoor Arena is a description of a new multi-use indoor arena in Dubai, United Arab Emirates that was under construction until construction stopped because of the late-2000s recession. Once completed, it will mainly be used for basketball, tennis, ice hockey, and other indoor sports, as well as music concerts. It was due to open in 2009 and will have a capacity of 10,000 spectators. It is part of the new mixed-use sports city currently being constructed in Dubai, Dubai Sports City and was to host The Legends Rock Dubai tennis tournament starting in 2009. It was postponed until 2010.
Document 4: National League (ice hockey): The National League (NL) is a professional ice hockey league in Switzerland. It is the top tier of the Swiss hockey league system and of the two-tier National League. Prior to the 2017–18 season, the league was officially called National League A.
Document 5: Vaillant Arena: Vaillant Arena (Eisstadion Davos) is an arena in Davos, Switzerland. It is primarily used for ice hockey and is the home arena of HC Davos. It holds 7,080 people, of which 3,280 are seated. Every year the Spengler Cup is played in this arena.
Document 6: List of AHL seasons: The American Hockey League is a minor professional ice hockey league in the United States and Canada. It serves as the top developmental league for the National Hockey League. The league played its first season in 1936 as the International-American Hockey League, a "circuit of mutual convenience" formed when the Northeast-based Canadian-American Hockey League and the Midwest-based International Hockey League agreed to play an interlocking schedule. After two seasons, the leagues formally merged into a unified league under the I-AHL name. After the 1939–40 season, the league became known as the American Hockey League.
Document 7: SC Bern: Schlittschuh Club Bern ("Ice-skating Club Bern" in English) is an ice hockey team based in Bern, Switzerland. They play in the National League (NL), the top tier of the Swiss hockey league system. For the 16th time in a row, the club is the most attended team in Europe for the 2016–17 season, averaging 16,399 spectators.
Document 8: Gavlerinken Arena: Gavlerinken Arena, formerly known as Läkerol Arena (2006–2014) and Gavlerinken (1967–2006), is an indoor sporting arena located in Gävle, Sweden. The capacity of the arena is 8,585 for ice hockey games and 11,000 for concerts which makes it the 5th largest ice hockey arena in Sweden. The arena is the home arena of the Brynäs IF ice hockey team.
Document 9: Tyrolean Ice Arena: Tiroler Wasserkraft Arena is an indoor sporting arena located in Innsbruck, Austria. The arena has a capacity of 3,000 people and was built in 2005 for the 2005 World Ice Hockey Championships. It is currently the home arena of HC Innsbruck who play in the Austrian Hockey League.
Document 10: St. Galler Kantonalbank Arena: St. Galler Kantonalbank Arena, formerly the Diners Club Arena, and originally known as Eishalle Lido, is an indoor sporting arena located in Rapperswil, Switzerland. The capacity of the arena is 6,100 and was built in 1987. It is the home arena of the Rapperswil-Jona Lakers ice hockey team. The arena was completely re-done in 2005, and changed its name following corporate sponsorship from Diners Club International. Its name was changed again in 2016 after a new sponsorship deal with naming rights was agreed with St. Galler Kantonalbank.
Document 11: Genève-Servette HC: The Genève-Servette HC (also called "Servette" or "GSHC") is a professional ice hockey club based in Geneva, Switzerland and competing in the National League, the top tier of the Swiss hockey league system. The team plays their home games at the Patinoire des Vernets, which has a seating capacity of 7,135. During the 2015-16 regular season, the GSHC was the fourth most attended team in Switzerland, averaging 6,556 spectators.
Document 12: National Lacrosse League: The National Lacrosse League (NLL) is a men's professional box lacrosse league in North America. Headquartered in Conshohocken, Pennsylvania, the NLL currently has eleven teams; seven in the United States and four in Canada. Unlike other lacrosse leagues which play in the summer, the NLL plays its games in the winter and spring, from January to June. Each year, the playoff teams battle for the Champion's Cup. The NLL has averaged between 9,400 and 10,700 spectators per game each year since 2004.
Document 13: NHL 17: NHL 17 is an ice hockey simulation video game developed by EA Canada and published by EA Sports. It is the 26th installment in the "NHL" game series and was released for the PlayStation 4 and Xbox One consoles on September 13, 2016 in North America and September 15 in Europe.
Document 14: Valascia: Valascia is an indoor sporting arena located in Ambrì, Switzerland. The capacity of the arena is 6,500 and was built in 1959. It is the home arena of the HC Ambri-Piotta ice hockey team of the National League (NL). The ends of arena are open air, making a hockey being played there partially outdoor.
Document 15: National Hockey League: The National Hockey League (NHL; French: "Ligue nationale de hockey—LNH" ) is a professional ice hockey league currently comprising 31 teams: 24 in the United States and 7 in Canada. Headquartered in New York City, the NHL is considered to be the premier professional ice hockey league in the world, and one of the major professional sports leagues in the United States and Canada. The Stanley Cup, the oldest professional sports trophy in North America, is awarded annually to the league playoff champion at the end of each season.
ground_truth: National League