Your dates are slightly off. "Kawamoto travels to Indonesia on September 15, and Stephi visits Japan on September 17." https://natalie.mu/music/news/299015 The period of study abroad is one month. From September 15, Kawamoto visited Indonesia (* Returned to participate in the handshake meeting on the way ※), and Stephi visited Japan from September 17th https://news.nifty.com/article/entame/showbizd/12257-085464/