egison, 296 bytes

Result

AC

Duration

1810ms

Code [DL]

      (define $repl
        (lambda []
          (do {(let {
            [$x (unpack (io (read-line)))]} 
            (writeChar (if (equal (nth 2 x) (nth 3 x)) (nth 2 x) (nth 5 x))))
            (write "\n")}
            (repl))))

(define $main
  (lambda [$args]
    (do {[(repl)]}
      [])))

stdin

574 473
277 762
258 815
966 487
542 443
561 168
122 553
528 211
183 884
877 853
411 911
789 998
345 831
363 639
597 772
311 197
637 579
393 379
235 356
411 118
889 114
577 995
978 751
636 355
161 553
958 484
519 819
133 339
838 686
955 655
662 369
425 739

stdout

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

stderr

egison: <stdin>: hGetLine: end of file

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffdd156ff30 /* 6 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55e13571fc00 /* 6 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/ln", ["ln", "-s", "/volume/CODE", "/tmp/code.segi"], 0x55e13571fc20 /* 6 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} ---
13    execve("/bin/cat", ["cat", "-"], 0x55e13571fc18 /* 6 vars */) = 0
14    execve("/usr/bin/egison", ["/usr/bin/egison", "/tmp/code.segi"], 0x55e13571fc28 /* 6 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} ---
16    +++ exited with 0 +++
18    +++ exited with 0 +++
17    +++ exited with 0 +++
15    +++ exited with 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=54, si_stime=15} ---
19    execve("/bin/rm", ["rm", "-f", "/tmp/code.segi"], 0x55e13571fbc0 /* 6 vars */) = 0
19    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=19, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++