python3, 52 bytes

Result

ERROR

Duration

630ms

Code [DL]

while 1:s=input();print(s[:s.find("__")].count("|"))

stdin

|||_||____
||_|||_|__
|__|_|||__
|||||__|__
||_||__|__
|_|__|_||_
|__||___||
|___|_||__
||||_|||||
|__|__|_||
||||_||___
|||__||_||
|___||||__
||________
|_|_||_|__
|_|__|__|_
||_|__|___
|__|||_|||
|_|___||||
|||_||||__
|_|||___||
|__|||||_|
|___||||||
||__||__||
|_||__||_|
|__||||___
|_|____||_
||_____|||
|||___||_|
|__||_|||_

stdout

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

stderr

Traceback (most recent call last):
  File "/volume/CODE", line 1, in <module>
    while 1:s=input();print(s[:s.find("__")].count("|"))
EOFError: EOF when reading a line

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7fff3235c5e0 /* 7 vars */) = 0
12    execve("/usr/bin/python3", ["/usr/bin/python3", "/volume/CODE"], 0x5582a9480d50 /* 7 vars */ <unfinished ...>
11    execve("/bin/cat", ["cat", "-"], 0x5582a9480d38 /* 7 vars */) = 0
12    <... execve resumed>)             = 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    +++ exited with 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=1, si_utime=1, si_stime=1} ---
10    +++ exited with 1 +++