Context: An English teacher named Seiji Hasumi (Hideaki Ito) is loved by his students and respected by his peers. He graduates from Harvard University with an MBA, and works at Morgenstern, a European investment bank, for two years. Hasumi returns to Japan to pursue high school teaching. However, his outward charm masks his true nature. In reality, Hasumi is a sociopath who is unable to feel empathy for other human beings. Specifically, he has a severe antisocial personality disorder. Having killed both of his parents and his former tutor at the age of fourteen, Hasumi turns into a fiendishly clever killer. During his time in the States, Hasumi meets a partner in crime, an American named Dave, who thinks he shares the same "hobby" as Hasumi killing people for fun. The two can be seen carrying buckets full of human blood, bones, and organs somewhere, giving off the notion that they committed numerous murders while working together. Hasumi eventually kills his partner by knocking him out and burning him alive inside a barrel, stating that while Dave enjoys killing for fun, Hasumi does not. Back in Japan, Hasumi chooses to deal with problems like bullying and student sexual harassment, starting by dealing with the school cheating issue. Upon collecting all of the students' cell phones prior to their exams, Hasumi secretly uses a cell phone jammer to completely prevent any cheating during the test. The group of students that had cheated on previous exams became suspicious after none of the group's cell phones have service during the test and immediately suspect the adviser of the Radio Club, Tsurii - a loner Physics teacher. They are then confronted by Tsurii himself who clarifies that he was not responsible for the jamming. A man who regularly meets with the school to complain about students bullying his daughter, Rina, is murdered. Someone has replaced the bottles of water he kept around his house to scare off cats with kerosene, as the man is a chainsmoker the bottles soon catch fire and explode. Tsurii soon meets with the intelligent ringleader of the cheating group, Keisuke, revealing his suspicions of Hasumi. Tsurii explains he has dug into Hasumi's past and found strange details, such as at another school where Hasumi started his teaching career that later had four student suicides. During this time, however, Hasumi had bugged the room and learned of Tsurii's suspicion, and confronts him on a train, murdering him and making his death appear as a hanging suicide. Hasumi then confronts Keisuke after the announcement of Tsurii's suicide causes him to panic. Hasumi knocks Keisuke out and ties him up until the end of school, after which Hasumi tortures him into admitting that he and his friends were indeed cheating. Hasumi checks that Keisuke didn't tell others of Tsurii's suspicions, before killing him and hiding his body. During the same time period, Hasumi is brought to the attention of a blackmail case from one of his students. A store owner, Meka, caught a female student, Miya, shoplifting but swears not to charge her for it. However, PE teacher Shibahara blackmails Miya, as he has recorded her admission of shoplifting, into giving him sexual favors or risk being charged. Hasumi, assures Miya that a blackmail and statutory rape case is more serious than shoplifting and affirms to her that she is safe from the law and no longer needs to succumb to the blackmail. Miya later meets Hasumi on the school roof, she thanks him with a hug that advances into a kiss and the two become lovers. In the meantime, Hasumi finds out about art teacher Kume's sexual relationship with a male student; he blackmails Kume into lending him his luxury apartment. Hasumi later takes Miya to the apartment and the two have sex. Hasumi presses Miya into giving him access to an online private discussion board that his students use, anonymously making claims about the murder of Rina's father, accusing delinquent student Tadenuma, who had targeted Rina online previously. After a fight breaks out at the school, Hasumi invites Tadenuma out for a drink and murders him; the students later assume that Tadenuma ran away from home. Events have passed until Hasumi's homeroom students are 
 Question: Who is the advisor of the radio club?
Output: tsurii