1. Chuo University Suginami High School 2-7-1 Imagawa, Suginami-ku, Tokyo, 167-0035, Japan mkitani626@g.chuo-u.ac.jp
2. Department of Applied Mathematics, Tokyo University of Science 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan hide-murakami@rs.tus.ac.jp
3. Department of Applied Mathematics, Tokyo University of Science 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan hiro@rs.tus.ac.jp