user: Extract the special guests that Taylor Swift had on her 1989 Tour in 2015. Separate them with a comma.

assistant: <think>
Below is the complete list of special guests who appeared onstage or performed with Swift on the 1989 World Tour.

May 15, 2015 – Las Vegas: "Tenerife Sea" with Ed Sheeran
May 30, 2015 – Detroit: "Radioactive" with Dan Reynolds of Imagine Dragons; Martha Hunt & Gigi Hadid.
June 6, 2015 – Pittsburgh: "Pontoon" with Little Big Town.
June 12, 2015 – Philadelphia: "Cool Kids" with Echosmith; Cara Delevingne & Mariska Hargitay.
June 13, 2015 – Philadelphia: "Fight Song" with Rachel Platten; Mariska Hargitay.
June 27, 2015 – London: Gigi Hadid, Kendall Jenner, Serena Williams, Martha Hunt, Karlie Kloss and Cara Delevingne.
July 10, 2015 – East Rutherford: "Can't Feel My Face" with The Weeknd; Heidi Klum and United States women's national soccer team; Lily Aldridge, Lena Dunham, Gigi Hadid and Hailee Steinfeld.
July 11, 2015 – East Rutherford: "Jealous" with Nick Jonas; Gigi Hadid, Martha Hunt, Lily Aldridge, Candice Swanepoel, Behati Prinsloo, Karlie Kloss, and Uzo Aduba.
July 13, 2015 – Washington, D.C.: "Royals" with Lorde.
July 14, 2015 – Washington, D.C.: "Want to Want Me" with Jason Derulo.
July 18, 2015 – Chicago: "Honey, I'm Good." with Andy Grammer; Serayah.
July 19, 2015 – Chicago: "Take Your Time" with Sam Hunt; Andreja Pejić & Lily Donaldson.
July 24, 2015 – Foxborough: "Shut Up and Dance" with Walk the Moon.
July 25, 2015 – Foxborough: "Classic" with MKTO.
August 1, 2015 – Vancouver: "Am I Wrong" with Nico & Vinz.
August 8, 2015 – Seattle: "Trap Queen" with Fetty Wap; Ciara and Russell Wilson.
August 14, 2015 – Santa Clara: "Worth It" with Fifth Harmony.
August 15, 2015 – Santa Clara: "Black Magic" with Little Mix; Joan Baez and Julia Roberts.
August 21, 2015 – Los Angeles: "Counting Stars" with Ryan Tedder of OneRepublic; Kobe Bryant presenting Swift with a banner hung on the Staples Center rafters in honor of Swift's 16 sold out shows, the most of any recording artist at the arena.
August 22, 2015 – Los Angeles: "White Horse" with Uzo Aduba; Chris Rock, Matt LeBlanc and Sean O'Pry; "Doubt" and "Family Affair" with Mary J. Blige.
August 24, 2015 – Los Angeles: "Goodbye Earl" with Natalie Maines of the Dixie Chicks; Ellen DeGeneres; "You Oughta Know" with Alanis Morissette.
August 25, 2015 – Los Angeles: "Dreams" with Beck and St. Vincent; "All of Me" with John Legend.
August 26, 2015 – Los Angeles: "Good for You" with Selena Gomez; "Smelly Cat" with Lisa Kudrow; "Mirrors" with Justin Timberlake.
August 29, 2015 – San Diego: "Cheerleader" with OMI; "Complicated" with Avril Lavigne.
September 9, 2015 – Houston: "See You Again" with Wiz Khalifa.
September 16, 2015 – Indianapolis: "If I Die Young" with The Band Perry.
September 18, 2015 – Columbus: "Cool Kids" with Sydney Sierota of Echosmith.
September 21, 2015 – Kansas City: "Every Mile a Memory" with Dierks Bentley.
September 25, 2015 – Nashville: "Love Me Like You Mean It" with Kelsea Ballerini; "I Don't Want to Miss a Thing" with Steven Tyler of Aerosmith; "When You Say Nothing at All" with Alison Krauss.
September 26, 2015 – Nashville: "Bleeding Love" with Leona Lewis; "(I Can't Get No) Satisfaction" with Mick Jagger of The Rolling Stones.
September 29, 2015 – St. Louis: "The Fix" with Nelly, and "Hot in Herre" with Nelly and Haim. To celebrate Haim's last night on the tour, Swift invited them to join her onstage as back-up dancers for Nelly.
October 2, 2015 – Toronto: "John Cougar, John Deere, John 3:16" and "Somebody Like You" with Keith Urban.
October 3, 2015 – Toronto: "Boom Clap" with Charli XCX.
October 17, 2015 – Arlington: "Love Me like You Do" with Ellie Goulding.
October 21, 2015 – Greensboro: "Little Red Wagon" with Miranda Lambert.
October 24, 2015 – Atlanta: "Talking Body" with Tove Lo.
October 27, 2015 – Miami: Dwyane Wade presenting Swift a "13" numbered jersey in honor of Swift's lucky number and his 13th season with the Miami Heat; "Give Me Everything" with Pitbull; "Livin' la Vida Loca" with Ricky Martin.
October 31, 2015 – Tampa: "Here" with Alessia Cara; "Let It Go" with Idina Menzel. During "Style", before "Let It Go" was performed, Swift wore an Olaf costume while Menzel wore her in-voice character Elsa, both from Frozen, in honor of Halloween.</think>
Ed Sheeran, Dan Reynolds, Martha Hunt, Gigi Hadid, Little Big Town, Echosmith, Cara Delevingne, Mariska Hargitay, Rachel Platten, Mariska Hargitay, Gigi Hadid, Kendall Jenner, Serena Williams, Martha Hunt, Karlie Kloss, Cara Delevingne, The Weeknd, Heidi Klum, United States women's national soccer team, Lily Aldridge, Lena Dunham, Gigi Hadid, Hailee Steinfeld, Nick Jonas, Gigi Hadid, Martha Hunt, Lily Aldridge, Candice Swanepoel, Behati Prinsloo, Karlie Kloss, Uzo Aduba, Lorde, Jason Derulo, Andy Grammer, Serayah, Sam Hunt, Andreja Pejić, Lily Donaldson, Walk the Moon, MKTO, Nico & Vinz, Fetty Wap, Ciara and Russell Wilson, Fifth Harmony, Little Mix, Joan Baez, Julia Roberts, Ryan Tedder of OneRepublic, Kobe Bryant, Uzo Aduba, Chris Rock, Matt LeBlanc, Sean O'Pry, Mary J. Blige, Natalie Maines of the Dixie Chicks, Ellen DeGeneres, Alanis Morissette, Beck, St. Vincent, John Legend, Selena Gomez, Lisa Kudrow, Justin Timberlake, OMI, Avril Lavigne, Wiz Khalifa, The Band Perry, Sydney Sierota of Echosmith, Dierks Bentley, Kelsea Ballerini, Steven Tyler of Aerosmith, Alison Krauss, Leona Lewis, Mick Jagger of The Rolling Stones, Nelly, Haim, Keith Urban, Charli XCX, Ellie Goulding, Miranda Lambert, Tove Lo, Dwyane Wade, Pitbull, Ricky Martin, Alessia Cara, Idina Menzel

user: which band sold the most albums of all time?

assistant: The Beatles.

Perhaps unsurprisingly, British rock band The Beatles are top of the list for best-selling artists worldwide, with 183 million units certified sales.

The Beatles were an English rock band, formed in Liverpool in 1960, that comprised John Lennon, Paul McCartney, George Harrison and Ringo Starr. They are regarded as the most influential band of all time and were integral to the development of 1960s counterculture and popular music's recognition as an art form.

user: How do I cast on a knitting project?

assistant: Casting on is how to make the first row of stitches. Each method of casting on can look and feel slightly different (such as various levels of stretchiness and flexibility) so most knitters have their preferred cast on method. Many use the long-tail cast on method which can work for many projects.  First, measure the length of yarn that is about 4 times as long as the width of your project. For example, if the width of your project is 10 inches, measure out a 40 inch piece of yarn. Next, time a slip knot. Then, place the slip knot on your dominant hand’s needle with the yarn tail closest to you (the tail is the length you measured out). Hold both strands of yarn with your non-dominant hand. Spread the two strands of yarn out with your thumb and forefinger, then bring the knitting needle in your right hand to the front of the tail of yarn draped over your thumb. Bring the needle back, up and through the loop toward your thumb loop, then push the needle back and under the forefinger loop, allowing the needle to catch the forefinger loop and allowing the thumb loop to fall off under the needle. That’s your first cast on stitch. Repeat the steps for the total number of stitches you need.