wren, 84 bytes

Result

AC

Duration

787ms

Code [DL]

import"io"for Stdin
var s
while(1)System.print((s=Stdin.readLine())[s[1]!=s[2]?4:2])

stdin

197 994
766 668
915 119
397 725
635 358
127 724
452 812
899 882
358 512
179 296
687 979
518 139
961 223
977 971
939 434
366 634
713 334
978 872
245 453
377 755
169 934
871 241
719 825
822 866
411 811
562 829
114 668
773 171
559 997
677 996
344 399
833 339

stdout

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

stderr

Subscript out of bounds.
[/volume/CODE line 3] in (script)

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffd0ed51bd0 /* 9 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x55b766bb5d30 /* 9 vars */) = 0
12    execve("/root/wren", ["/root/wren", "/volume/CODE"], 0x55b766bb5d40 /* 9 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    +++ 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} ---
10    +++ exited with 0 +++