Background: AKB48 (pronounced A.K.B. Forty-eight) are a Japanese idol girl group named after the Akihabara (Akiba for short) area in Tokyo, where the group's theater is located. The group has expanded since then to include over 130 members as of December 2015, aged from their early teens to their mid-20s. AKB48's producer, Yasushi Akimoto, wanted to form a girl group with its own theater (unlike pop groups performing occasional concerts and seen on television) and performing daily so fans could always see them live. This "idols you can meet" concept includes teams which can rotate performances and perform simultaneously at several events and "handshake" events, where fans can meet group members.
Context: AKB48 was founded as "idols you can meet". The group's chief producer, Yasushi Akimoto, said that his goal was to create a unique idol group which, unlike other idol groups which perform occasional concerts and appear primarily on television, would perform regularly in its own theater. The AKB48 Theater is in the Don Quijote store in Akihabara, Tokyo.  The group is split into several teams, reducing its members' workload (since the theater's near-daily performance is by only one team) and enabling AKB48 to perform simultaneously in several places. According to former member Misaki Iwasa, each team has its own theme. Team A represents freedom; Team B is idol-like, with cute costumes, and Team K has a strong, powerful image. According to an early press release the group was intended to have 16 members on each of three teams, for a total membership of 48; but its membership has varied over time, and has exceeded 120 people. New members are called trainees (Yan Jiu Sheng , kenkyusei) who are understudies for the group, performing occasionally in the theater as a team. In addition to their performances with the group, members are promoted by the Japanese mass media. AKB48 regularly hosts events, where fans can interact with the members, such as taking pictures or shaking hands with the members.  The group members' ages range from their early teens to over 20, and they are selected from regular auditions. Members are not allowed to date, and must be well-behaved; any violation of these restrictions is to be punished, possibly by expulsion from the group. AKB48 has a system that allows members to "graduate" from the group when they are older and are replaced by trainees who are promoted. Monica Hesse of The Washington Post described the AKB48 audition process as "rolling American Idol-esque".  In October 2006 AKB48 announced auditions for Team B, and 13 girls were chosen out of 12,828 applicants in December. The group's first DefStar Records single, "Aitakatta", was recorded by 20 members of Teams A and K and released on October 25. It debuted at number 12 on the Oricon weekly singles chart, selling 25,544 copies in its first six weeks, and remained on the chart for a total of 65 weeks. On November 3-4 AKB48 performed its first concert, "AKB48 First Concert: Aitakatta ~Hashira wa Nai ze!~" at Nippon Seinenkan in Shinjuku. The group performed "Aitakatta" on the New Year's Eve TV program 58th NHK Kohaku Uta Gassen as a part of the "Nihon ga Hokoru Saisentan! Special Medley". At 43 members, the group set a program record for the most people in one group onstage simultaneously. AKB48 made its first lineup change in December, transferring Kazumi Urano, Shiho Watanabe and Natsumi Hirajima from Team A to Team B as supporting members.  AKB48's second major-label single, "Seifuku ga Jama o Suru", was released on January 31, 2007 and debuted at number seven on the Oricon Top 10 chart. Its music video and lyrics hinted at the subject of enjo kosai (compensated dating, remotely related to escort services outside Japan), triggering controversy and negative reviews. On March 18 AKB48 released "Keibetsu Shiteita Aijo"; debuting at number eight on the Oricon chart, it dropped to number 98 in its second week. The group's second concert, "AKB48 Haru no Chotto dake Zenkoku Tour ~Madamada daze AKB48!~" on March 10, had poor ticket sales.  In April 2007 AKB48 posted its Team B roster on its website, with five fewer members than originally announced; for the first time, its membership numbered 48. The group's fourth single, "Bingo!", was released on July 18. AKB48's sixth single, "Yuhi o Miteiru ka?", was released on Halloween 2007 and sold 18,429 copies (the least of all the group's singles).  AKB48's 16th single, "Ponytail to Chouchou", was released on May 26, 2010. Its sales exceeded those of the previous single, with over 400,000 copies sold on its first day and over 513,000 in its first week. On April 27 Anime Expo, the largest anime convention in the United States, announced that AKB48 would be a guest of honor and the group performed on July 1 at the Nokia Theatre.  On October 23 AKB48 represented Japan at the seventh Asia Song Festival, organized by the Korea Foundation for International Culture Exchange, at Seoul Olympic Stadium. Four days later the group released its 18th single, "Beginner". It sold 826,989 copies in its first week, the highest first-week sales for a female idol group single. AKB48 member Mayu Watanabe appeared on the cover of the December issue of the idol magazine UP to boy with Airi Suzuki from the Japanese girl group Cute, the first gravure collaboration between Hello! Project and AKB48.  In November 2010, AKB48 participated in several events outside Japan. On November 20, 12 members of the group performed at the Japanese Pop Culture Festival in Moscow. AKB48 performed at the Cool Japan forum in Singapore as part of Anime Festival Asia X, and at the Singapore Toy, Games and Comics Convention. Group graduates in 2010 included second-generation member Erena Ono, who left on September 27 to pursue an acting career overseas.  The group's first 2011 single, "Sakura no Ki ni Naro", was released on February 16. It sold 655,000 copies on its first day, surpassing "Beginner's" first-day sales of 568,000. By the end of its first week the single sold 942,479 copies, the group's best and the fastest sales in Japan since 2000.  On February 21 AKB48 announced its third album, Koko ni Ita Koto (kokoniitakoto), which would include 11 new tracks and was scheduled for an April 6 release. Due to the 2011 Tohoku earthquake and tsunami, the group stopped its AKB48 Theater performances and canceled some of its public events. AKB48 began the "Dareka no Tame ni" (Shui kanotameni, lit. "For someone's sake") project, collecting donations for earthquake and tsunami relief. One of its concert venues, the Yokohama Arena, was used for a two-day charity event beginning on March 26 and 12 AKB48 members attended the Okinawa International Movie Festival that day for the same purpose. On March 15, AKB48 announced that Y=500 million would be donated by the group, its sister groups SKE48, SDN48 and NMB48 and associates of AKS, its management company. Koko ni Ita Koto's release was postponed until June 8, with part of the album's proceeds donated to disaster victims. On April 1 the group released the charity single "Dareka no Tame ni (What can I do for someone?)" (Shui kanotameni -What can I do for someone?-) on the Recochoku website as a digital download, with all proceeds earmarked for earthquake and tsunami relief.
Question: how did this event do?

Answer:
Four days later the group released its 18th single, "Beginner". It sold 826,989 copies in its first week, the highest first-week sales for a female idol group single.