node, 131 bytes

Result

AC

Duration

849ms

Code [DL]

for(s of (""+require("fs").readFileSync(0)).split(/\n/)){
if(s)console.log((s+"a").slice(0,s.indexOf("__")).split("|").length-1);
}

stdin

|_|_|||__|
|_|__||__|
|||__|_|__
||||_____|
|__|_|___|
|||___||_|
|||_|__|__
|||__|__||
|____|_||_
||_|_____|
|_||||_|__
|__|______
||_||||||_
|___|||||_
|__|_|||||
|||_||___|
|__|||||||
|____|_|__
||_____|||
|___||_|__
|_|__|||||
||__||___|
||___|||__
||_|_|_||_
||_____|_|
|||||_|||_
|||||__|||
|__|_____|
|||__||_|_
|||_||||__

stdout

5
2
3
4
1
3
4
3
1
3
6
1
8
1
1
5
1
1
2
1
2
2
2
6
2
8
5
1
3
7

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc259b0e00 /* 7 vars */) = 0
12    execve("/usr/bin/node", ["/usr/bin/node", "/volume/CODE"], 0x5634b8fc2d40 /* 7 vars */ <unfinished ...>
11    execve("/bin/cat", ["cat", "-"], 0x5634b8fc2d30 /* 7 vars */) = 0
11    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=11, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
12    <... execve resumed>)             = 0
17    +++ exited with 0 +++
16    +++ exited with 0 +++
14    +++ exited with 0 +++
15    +++ exited with 0 +++
13    +++ exited with 0 +++
18    +++ exited with 0 +++
12    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=0, si_utime=6, si_stime=2} ---
10    +++ exited with 0 +++