Question: What is the nationality of "Yen" a Singer-songwriter band?

full_context: Document 1: The Samans: The Samans (), is a Chinese Industrial metal band that was formed at 2007 in Changchun, Jilin. Currently it has five members, Lifu Wang (Lead Vocal)、Yaxin Gao (Programme/Samples)、Zhichao Ren (Guitar)、Xiaoyu Cui (Guitar)、Ji Qi(Bass). The name of their band is from their five members' (those who from Northeast of China and Inner Mongolia Region) Religion. The member chose to use "The Samans" as their band's English name instead of "Shaman" because they insist it doesn't spell like that in their national language. Most of their songs are in English.
Document 2: Musical composition: Musical composition can refer to an original piece of music, either a song or an instrumental music piece, the structure of a musical piece, or the process of creating or writing a new song or piece of music. People who create new compositions are called composers in classical music. In popular music and traditional music, the creators of new songs are usually called songwriters; with songs, the person who writes new words for a song is the lyricist. "Composition" is the act or practice of creating a song or other piece of music. In many cultures, including Western classical music, the act of composing typically includes the creation of music notation, such as a sheet music "score", which is then performed by the composer or by other instrumental musicians or singers. In popular music and traditional music, songwriting may involve the creation of a basic outline of the song, called the lead sheet, which sets out the melody, lyrics and chord progression. In classical music, orchestration (choosing the instruments of a large music ensemble such as an orchestra which will play the different parts of music, such as the melody, accompaniment, countermelody, bassline and so on) is typically done by the composer, but in musical theatre and in pop music, songwriters may hire an arranger to do the orchestration. In some cases, a pop or traditional songwriter may not use written notation at all, and instead compose the song in her mind and then play, sing and/or record it from memory. In jazz and popular music, notable sound recordings by influential performers are given the weight that written or printed scores play in classical music.
Document 3: Yen (band): Yen is a German rock band. The name of the band stems from singer/songwriter Yen-Hwei Anetzberger. "Yen-Hwei" means "Abundant grace" in Mandarin.
Document 4: Singer-songwriter: Singer-songwriters are musicians who write, compose, and perform their own musical material, including lyrics and melodies.
Document 5: Dạ Nhật Yến: Dạ Nhật Yến (born October 12), professionally known as Yenn, is a Vietnamese American singer and dancer. She was born in Saigon, and later immigrated to the United States. There, Yenn was raised in Ada, Minnesota, and later moved to Southern California. She appeared in Asia Entertainment since 2000 DVD musical shows, generating many choreographic and musical masterpieces. Yenn recorded and released ten albums in her native language through her former label. With a series of best-selling CDs and DVDs helped introduce her to the international pop scene, Yenn developed a devoted following throughout Europe, Asia and Australia with her captivating high-energy performances. She is well known for songs such as "Adult Ceremony", "Voi Anh Dem Nay", "Voulez Vous", "Dem Buon Nhu Thanh Ca", and "Co Nhung Chuyen Tinh Khong La Tram Nam". She released her first US single entitled "So Good to be Wrong" along with "Show Me Your Heaven".
Document 6: Evan: Evan is a Welsh masculine given name derived from "Iefan", a Welsh form for the name John. In other languages it could be compared to "Ivan", "Ian", and "Juan"; the name John itself is derived from the ancient Hebrew name Yəhôḥānān, which means "YHWH is gracious". Evan also comes from the Gaelic word "Eóghan" meaning "youth" or "young warrior" and Scots for "right-handed". In Hebrew, the actual non-proper noun, "evan/even/eban/eben", literally means "rock". It can also be the shortened version of the Greek name "Evangelos" (meaning messenger, or "Evander" (meaning good man). The old English translation of the name "Evan" could also be interpreted as "Heir of the Earth" or "The King". The name is also occasionally given to females, as with actress Evan Rachel Wood. It may be encountered as a surname, but Evans is usual.
Document 7: Die Rhöner Säuwäntzt: Die Rhöner Säuwäntzt are a Skiffle-Bluesband from Eichenzell-Lütter in Hessen, Germany. The line-up consists of Martin Caba, Christoph Günther and Christoph Leipold playing Skiffle-Blues with lyrics based on Rhön Mountains dialect and other Hessian dialects varieties. The expression "Säuwäntzt" means pork belly and refers also to untidy or unruly children and youth.
Document 8: Tim Ten Yen: Tim Ten Yen, also known as "TTY", is an English recording artist. He has been called the "Sensational Singing Salaryman". and championed by influential English disc jockey Steve Lamacq as a "cult figure of the future".
Document 9: List of songs written and performed by David Cook: The list of songs written and performed by David Cook comprises original songs recorded by American singer-songwriter David Cook for his studio albums, cover versions of songs by other artists performed by Cook, and original songs written by Cook that were recorded and released by other artists.
Document 10: Songwriter: A songwriter is a professional who is paid to write lyrics and melodies for songs, typically for a popular music genre such as rock or country music. A songwriter can also be called a composer, although the latter term tends to be used mainly for individuals from the classical music genre. The pressure from the music industry to produce popular hits means that songwriting is often an activity for which the tasks are distributed between a number of people. For example, a songwriter who excels at writing lyrics might be paired with a songwriter with the task of creating original melodies. Pop songs may be written by group members from the band or by staff writers – songwriters directly employed by music publishers. Some songwriters serve as their own music publishers, while others have outside publishers.
Document 11: German nouns: German nouns have a grammatical gender, as in many related Indo-European languages. They can be masculine, feminine, or neuter, even words for objects without (obvious) masculine or feminine characteristics like 'bridge' or 'rock'. They are also declined (change form) depending on their grammatical case (their function in a sentence) and whether they are singular or plural. German has four cases, nominative, accusative, dative and genitive.
Document 12: List of songs recorded by Björk: Icelandic singer and songwriter Björk has recorded more than one hundred songs for eight studio albums, two soundtrack albums, a compilation album, five remix albums and two collaboration albums. She is the sole writer and producer of most of the songs included in her albums. She also sometimes plays instruments during her recording sessions. Moreover, she has provided credited and uncredited contributions on songs recorded by other artists, including background vocals, songwriting, remixing and production.
Document 13: Paul Kelly (Australian musician): Paul Maurice Kelly {'1': ", '2': ", '3': ", '4': "} (born 13 January 1955) is an Australian rock music singer-songwriter, guitarist, and harmonica player. He has performed solo, and has led numerous groups, including the Dots, the Coloured Girls, and the Messengers. He has worked with other artists and groups, including associated projects Professor Ratbaggy and Stardust Five. Kelly's music style has ranged from bluegrass to studio-oriented dub reggae, but his core output straddles folk, rock, and country. His lyrics capture the vastness of the culture and landscape of Australia by chronicling life about him for over 30 years. David Fricke from "Rolling Stone" calls Kelly "one of the finest songwriters I have ever heard, Australian or otherwise." Kelly has said, "Song writing is mysterious to me. I still feel like a total beginner. I don't feel like I have got it nailed yet".
Document 14: List of signature songs: A signature song is the one song (or, in some cases, one of a few songs) that a popular and well-established recording artist or band is most closely identified with or best known for, even if they have had success with a variety of other songs. There have also been instances where a film actor has acquired a signature song by giving a popular vocal performance in a feature. Signature songs can be the result of spontaneous public identification, or a marketing tool developed by the music industry to promote artists, sell their recordings, and develop a fan base.
Document 15: Melvin Endsley: Melvin Endsley (30 January 1934 – 16 August 2004) was a musician, singer, and songwriter best known for writing the song "Singing the Blues", along with over 400 songs recorded by hundreds of artists since 1956. Some of the artists that have recorded his songs include Johnny Cash, Marty Robbins, Andy Williams, Paul McCartney, Stonewall Jackson, and Ricky Skaggs. At the beginning of his career, Endsley recorded including RCA and MGM, however, his vocal recordings were commercially unsuccessful. In 1998, he was inducted into the Arkansas Entertainers Hall of Fame.
ground_truth: German