verilog, 113 bytes

Result

AC

Duration

821ms

Code [DL]

module c;reg[48:0]s;initial begin
while($fgets(s,1<<31))$write("%s",s[7:0]-s[15:8]?s[31:24]:s[7:0]);end
endmodule

stdin

331 385
611 115
176 319
944 872
849 136
682 886
856 869
827 638
137 572
644 335
194 941
655 551
488 861
387 879
255 657
427 772
331 442
388 488
579 471
918 833
974 279
944 728
442 257
644 454
447 114
472 275
823 276
754 447
512 717
622 662
463 368
864 662

stdout

1 1 6 4 9 8 6 7 7 3 4 5 8 7 5 7 4 8 9 8 4 4 2 4 1 2 3 4 2 6 3 6 

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7fff0a6f87f0 /* 9 vars */) = 0
11    execve("/usr/local/bin/iverilog", ["/usr/local/bin/iverilog", "-o", "/tmp/code", "/volume/CODE"], 0x561f33a39d50 /* 9 vars */) = 0
12    execve("/bin/sh", ["sh", "-c", "/usr/local/lib/ivl/ivlpp  -L -F\""...], 0x7fff80d951a0 /* 9 vars */) = 0
14    execve("/usr/local/lib/ivl/ivl", ["/usr/local/lib/ivl/ivl", "-C/tmp/ivrlh3999c4e2", "-C/usr/local/lib/ivl/vvp.conf", "--", "-"], 0x563dc37cd290 /* 9 vars */) = 0
13    execve("/usr/local/lib/ivl/ivlpp", ["/usr/local/lib/ivl/ivlpp", "-L", "-F/tmp/ivrlg23999c4e2", "-f/tmp/ivrlg3999c4e2", "-p/tmp/ivrli3999c4e2"], 0x563dc37cd2a8 /* 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 0 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
12    +++ exited with 0 +++
11    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=0, si_utime=0, si_stime=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} ---
15    execve("/bin/cat", ["cat", "-"], 0x561f33a39d08 /* 9 vars */ <unfinished ...>
16    execve("/tmp/code", ["/tmp/code"], 0x561f33a39cf0 /* 9 vars */ <unfinished ...>
15    <... execve resumed>)             = 0
16    <... execve resumed>)             = 0
15    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=15, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
16    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=16, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
17    execve("/bin/rm", ["rm", "/tmp/code"], 0x561f33a39c98 /* 9 vars */) = 0
17    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=17, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++