Question: What is the type of musical composition that was used by the Korean female band Isak N Jiyeon?

Context paragraphs:
Isak N Jiyeon: Isak N Jiyeon (이삭 N 지연) was a Korean female duo formed by SM Entertainment in 2002 that has since been disbanded.  Jiyeon was involved in SM's project named The Grace, a four-member Korean girl group that sings, dances and acts.  Isak was featured in the SM Town albums and videos and continued to do a variety of work, such as being DJ and VJ for Arirang TV, MC work for various networks, and taking on small acting roles on network television.

List of musical forms by era: This is a list of musical forms and genres organized according to the eras of Classical music.  The form of a musical composition refers to the general outline of the composition, based on the sections that comprise it or on specific details that are unique to a certain type of composition.  For example, a rondo is based on alternation between familiar and novel sections (ABACA); a mazurka is defined by its meter and rhythm; a nocturne is based on the mood it creates, required to be inspired by or evocative of night.  This list summarizes these broadly defined forms and genres within the musical periods that they arose or became common.

Pulitzer Prize for Music: The Pulitzer Prize for Music is one of the seven American Pulitzer Prizes that are annually awarded for Letters, Drama, and Music.  It was first awarded in 1943.  Joseph Pulitzer did not call for such a prize in his will, but had arranged for a music scholarship to be awarded each year.  This was eventually converted into a full-fledged prize: "For a distinguished musical composition of significant dimension by an American that has had its first performance in the United States during the year."  Because of the requirement that the composition had its world premiere during the year of its award, the winning work had rarely been recorded and sometimes had received only one performance.  In 2004 the terms were modified to read: "For a distinguished musical composition by an American that has had its first performance or recording in the United States during the year."

Kenzie (songwriter): Kenzie (Korean 켄지 "Kenji", born Kim Yeon Jung, February 3, 1976 in Shimane-ken, Japan) is a composer signed under S.M. Entertainment.  She has composed dozens of songs for S.M. label-mates including BoA, Isak N Jiyeon, Super Junior, The Grace, TVXQ, Girls' Generation, SHINee, f(x), EXO, Red Velvet and NCT.

Park Kyung-won: Park Kyung-won (24 June 1901 – 7 August 1933) was, along with Kwon Ki-ok of the Republic of China Air Force, one of the earliest Korean female aviators. Though it is generally agreed that Kwon was the first female pilot, Park is still recognised as the first Korean female civilian pilot, as Kwon was trained by the Republic of China Air Force.  She was the subject of the controversial 2005 South Korean film "Blue Swallow", in which she was portrayed by actress Jang Jin-young.

Duet: A duet is a musical composition for two performers in which the performers have equal importance to the piece, often a composition involving two singers or two pianists.  It differs from a harmony, as the performers take turns performing a solo section rather than performing simultaneously.  A piece performed by two pianists performing together on the same piano is a "piano duet" or "piano four hands".  A piece for two pianists performing together on separate pianos is a "piano duo".

Schillinger System: The Schillinger System of Musical Composition, named after Joseph Schillinger (1895–1943) is a method of musical composition based on mathematical processes.  It comprises theories of rhythm, harmony, melody, counterpoint, form, and semantics (emotional meaning, as in movie music).

Lina (South Korean singer): Lee Ji-yeon (born February 18, 1984), better known by her stage name Lina is a South Korean singer and musical actress.  She debuted in 2002 as a member of South Korean R&B duo Isak N Jiyeon and disbanded in 2004.  She later re-debut as a member of South Korean girl group The Grace in 2005 and the group currently being inactive.  She currently active as a musical actress.

4 Intimate Nights with Beyoncé: 4 Intimate Nights with Beyoncé was the second residency show by American recording artist Beyoncé.  Held during four non-consecutive nights in August 2011 at the Roseland Ballroom in New York City, the concerts were part of Beyoncé's campaign in support of her fourth studio album "4" (2011).  All the songs on the standard version of the album, excluding "Start Over", were performed by her to a standing room-only audience of 3,200.  Beyoncé also sang some of her previous hits from her three prior studio albums as well as songs she recorded with former girl group Destiny's Child in the 1990s and early 2000s.  Wearing a linky gold sparkling mini-dress, she was backed by four female dancers and a 20-piece female band including a horn and orchestra section.

Tell Me Baby (album): Tell Me Baby is the debut and only Korean studio album by South Korean duo Isak N Jiyeon, a new 2002 group from SM Entertainment, released on September 3, 2002.

Supporting paragraphs: Isak N Jiyeon Duet
Answer: duet