ruby, 51 bytes

Result

WA

Duration

1036ms

Code [DL]

puts $<.chars.map{|c|c=c>='A'&&c=<'Z'?'1':'0'}.join

stdin

aBcdEFGhijkLMNOPQrStuvwXYZ

stdout

stderr

/volume/CODE:1: syntax error, unexpected '<'
...s $<.chars.map{|c|c=c>='A'&&c=<'Z'?'1':'0'}.join
...                              ^
/volume/CODE:1: warning: string literal in condition

strace

12    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc0dafa030 /* 9 vars */) = 0
13    execve("/bin/cat", ["cat", "-"], 0x55e997ee4d40 /* 9 vars */) = 0
14    execve("/usr/local/ruby-2.7.1/bin/ruby", ["/usr/local/ruby-2.7.1/bin/ruby", "/volume/CODE"], 0x55e997ee4d60 /* 9 vars */) = 0
13    +++ exited with 0 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
14    +++ exited with 1 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=1, si_utime=6, si_stime=3} ---
12    +++ exited with 1 +++