python3, 44 bytes

Result

AC

Duration

795ms

Code [DL]

while s:=input():print(s[2:5:2][s[1]!=s[2]])

stdin

478 851
188 654
731 984
963 661
613 221
277 771
547 476
788 553
755 252
446 498
214 448
571 719
417 951
152 252
842 249
366 466
355 561
577 634
448 889
693 432
659 894
533 335
265 635
491 455
928 115
876 682
653 253
981 931
422 284
544 998
331 634
637 336

stdout

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

stderr

Traceback (most recent call last):
  File "/volume/CODE", line 1, in <module>
    while s:=input():print(s[2:5:2][s[1]!=s[2]])
EOFError: EOF when reading a line

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffde046bcc0 /* 7 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x56526955bd38 /* 7 vars */ <unfinished ...>
12    execve("/usr/bin/python3", ["/usr/bin/python3", "/volume/CODE"], 0x56526955bd50 /* 7 vars */ <unfinished ...>
11    <... execve resumed>)             = 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 +++