https://zerojudge.tw/Submissions?problemid=d490&account=lucariotinliu@gmail.com#:~:text=%23include%3Ciostream%3E%0Ausing%20namespace%20std%3B%0Aint%20main()%0A%7B%0Aint%20a%2Cb%2Ci%2Csum%3D0%3B%0Acin%3E%3Ea%3E%3Eb%3B%0Afor(i%3Da%3Bi%3C%3Db%3Bi%2B%2B)%7B%0Asum%3Dsum%2Bi*(i%252%3D%3D0)%3B%0A%7D%0Acout%3C%3Csum%3B%0Areturn%200%3B%0A%7D
https://www.youtube.com/watch?v=dQw4w9WgXcQ