Question: How many cantons does the country which the Vallée de Joux is mainly in consist of?

Context paragraphs:
La Vallée District: La Vallée is a former district of the canton of Vaud, Switzerland, consisting of three municipalities in the Vallée de Joux.  The seat of the district was the village of Le Sentier.  La Vallée has been merged into Jura-North Vaudois District.

Lac de Joux: Lac de Joux is a lake in the Vallée de Joux in the Canton of Vaud, Switzerland.  With a surface area of 9.5 km², it is the largest lake in Switzerland lying above 1,000 metres.  Lac de Joux is located in the Jura Mountains.

Lac Brenet: Lac Brenet is a lake in the Vallée de Joux, canton of Vaud, Switzerland.  It is located north of the Lac de Joux, only 200 metres away.  Its elevation of 1002 metres is 2 metres below that of Lac de Joux.

Switzerland: Switzerland ( ), officially the Swiss Confederation, is a federal republic in Europe.  It consists of 26 cantons, and the city of Bern is the seat of the federal authorities.

Vallée de Joux: The Vallée de Joux is a valley of the Jura Mountains mainly in the Swiss Canton of Vaud.  The valley also continues into France (Département of Jura) at its higher, south-western, end.  Located 30 miles (50 km) north of Geneva and north-west of Lausanne, its mean elevation is over 3300 feet (1000 metres).  There are three Swiss lakes in the "Vallée de Joux" : the lac de Joux (around 6 miles (10 km) long), the lac Brenet and the lac Ter.  The French border runs along the northern edge of the valley until, about 10 km west of the lac de Joux, the base of the valley becomes French territory.  The valley then continues to climb gently towards the Lac des Rousses and the ski resort of Les Rousses.

Le Lieu: Le Lieu is a municipality in the canton of Vaud in Switzerland, located in the district of Jura-Nord Vaudois in the Vallée de Joux.

L'Abbaye: L'Abbaye is a municipality in the canton of Vaud, Switzerland, located in the Jura-Nord Vaudois district in the Vallée de Joux.  It takes its name from Lac de Joux Abbey, a Premonstratensian monastery.

Patek Philippe &amp; Co.: Patek Philippe & Co. is a Swiss watch manufacturer founded in 1851, located in Geneva and the Vallée de Joux.  It designs and manufactures timepieces and movements, including some of the most complicated mechanical watches.  It is considered by many experts and aficionados to be one of the most prestigious watch manufacturers.

Valjoux: Valjoux (for "Vallée de Joux", "Joux Valley") is a Swiss manufacturer of mechanical watch movements.  It is known primarily for chronograph ébauche movements that are used in a number of mid- to high-range mechanical watches: The company has been a part of ETA for a number of years and is a member of the Swatch Group.

Lac des Rousses: Lac des Rousses is a lake in Les Rousses, Jura department, Franche-Comté, France, close to the Vallée de Joux in Switzerland.  The lake drains through the Orbe (river) into Lac de Joux.

Supporting paragraphs: Vallée de Joux Switzerland
Answer: 26