Please answer the following question: Information: - Italy, officially the Italian Republic, is a unitary parliamentary republic in Europe. Located in the heart of the Mediterranean Sea, Italy shares open land borders with France, Switzerland, Austria, Slovenia, San Marino and Vatican City. Italy covers an area of and has a largely temperate seasonal climate and Mediterranean climate; due to its shape, it is often referred to in Italy as "lo Stivale" (the Boot). With 61 million inhabitants, it is the fourth most populous EU member state. - A boot is a type of footwear and a specific type of shoe. Most boots mainly cover the foot and the ankle, while some also cover some part of the lower calf. Some boots extend up the leg, sometimes as far as the knee or even the hip. Most boots have a heel that is clearly distinguishable from the rest of the sole, even if the two are made of one piece. Traditionally made of leather or rubber, modern boots are made from a variety of materials. Boots are worn both for their functionality protecting the foot and leg from water, extreme cold, mud or hazards (e.g., work boots may protect wearers from chemicals or use a steel toe) or providing additional ankle support for strenuous activities with added traction requirements (e.g., hiking) and for reasons of style and fashion. - Umbria, is a region of historic and modern central Italy. It is the only Italian region having neither a coastline nor a border with other countries. It includes the Lake Trasimeno, Marmore's Falls, and is crossed by the River Tiber. The regional capital is Perugia. Umbria is known for its landscapes, traditions, history, culinary delights, artistic legacy, and influence on culture. - TheMediterranean Sea (pronounced ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant. The sea is sometimes considered a part of the Atlantic Ocean, although it is usually identified as a separate body of water. - Arezzo is a city and "comune" in Italy, capital of the province of the same name, located in Tuscany. Arezzo is about southeast of Florence, at an elevation of above sea level. In 2013 the population was about 99,000. - France, officially the French Republic, is a country with territory in western Europe and several overseas regions and territories. The European, or metropolitan, area of France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean. Overseas France include French Guiana on the South American continent and several island territories in the Atlantic, Pacific and Indian oceans. France spans and had a total population of almost 67 million people as of January 2017. It is a unitary semi-presidential republic with the capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban centres include Marseille, Lyon, Lille, Nice, Toulouse and Bordeaux. - Slovenia, officially the Republic of Slovenia (Slovene: , abbr.: "RS"), is a nation state in southern Central Europe, located at the crossroads of main European cultural and trade routes. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and the Adriatic Sea to the southwest. It covers and has a population of 2.06million. It is a parliamentary republic and a member of the United Nations, European Union, and NATO. The capital and largest city is Ljubljana. - San Marino, officially the Republic of San Marino, also known as the Most Serene Republic of San Marino, is an enclaved microstate surrounded by Italy, situated on the Italian Peninsula on the northeastern side of the Apennine Mountains. Its size is just over , with a population of 33,562. Its capital is the City of San Marino and its largest city is Dogana. San Marino has the smallest population of all the members of the Council of Europe. - A mediterranean climate or dry summer climate is the climate typical of the lands in the Mediterranean Basin. The lands around the Mediterranean Sea form the largest area where this climate type is found, but it also is found in most of coastal California, in parts of Western and South Australia, in southwestern South Africa, sections of Central Asia, and in central Chile. - The Tiber (Latin "Tiberis", Italian "") is the third-longest river in Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing through Umbria and Lazio, where it is joined by the Aniene river, to the Tyrrhenian Sea, between Ostia and Fiumicino. It drains a basin estimated at . The river has achieved lasting fame as the main watercourse of the city of Rome, founded on its eastern banks. - Perugia is the capital city of both the region of Umbria in central Italy, crossed by the river Tiber, and of the province of Perugia. The city is located about north of Rome and south-east of Florence. It covers a high hilltop and part of the valleys around the area. The region of Umbria is bordered by Tuscany, Lazio, and Marche. The history of Perugia goes back to the Etruscan period; Perugia was one of the main Etruscan cities. The city is also known as the universities town, with the University of Perugia founded in 1308 (about 34,000 students), the University for Foreigners (5,000 students), and some smaller colleges such the Academy of Fine Arts "Pietro Vannucci" public athenaeum founded in 1573, the Perugia University Institute of Linguistic Mediation for translators and interpreters, the Music Conservatory of Perugia, founded in 1788, and others Institutes. - The Val di Chiana , Valdichiana , or Chiana Valley is an alluvial valley of central Italy , lying on the territories of the provinces of Arezzo and Siena in Tuscany and the provinces of Perugia and Terni in Umbria . What is the relationship between 'valdichiana' and 'tiber'?
A:
mouth of the watercourse