〇：up number down. 零：Bring this number to an end. 〇：The main\\ 零：char? He's not the main one. 〇：Of course, he's just the standard input\\ 零：like the key 〇：board 零：where the chars come from, of course. 〇：All the chars? 零：All but [[proc/self/fd/1|one]].