vlang, 78 bytes

Result

WA

Duration

905ms

Code [DL]

import os
fn main(){for a:=os.get_line() {
print(a[if a[1]==a[2]{2}else{4}])}}

stdin

599 991
334 841
296 992
288 389
698 118
199 997
493 935
877 355
948 482
485 884
443 285
685 249
411 771
133 632
638 633
831 363
113 234
429 997
319 227
824 449
577 757
577 759
237 936
445 449
425 273
716 618
155 116
277 961
549 763
239 939
973 329
552 294

stdout

stderr

/tmp/code.v:2:32: error: unexpected `{`, expecting `;` 
    1| import os
    2| fn main(){for a:=os.get_line() {
                                      ^
    3| print(a[if a[1]==a[2]{2}else{4}])}}

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffe88f26720 /* 7 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55de220f4d18 /* 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("/bin/cp", ["cp", "-f", "/volume/CODE", "/tmp/code.v"], 0x55de220f4d38 /* 7 vars */) = 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=0, si_stime=0} ---
14    execve("/root/v", ["/root/v", "run", "/tmp/code.v"], 0x55de220f4d80 /* 7 vars */) = 0
13    execve("/bin/cat", ["cat", "-"], 0x55de220f4d58 /* 7 vars */) = 0
13    +++ exited with 0 +++
10    --- 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 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=1, si_utime=1, si_stime=1} ---
10    +++ exited with 1 +++