wren, 85 bytes

Result

WA

Duration

926ms

Code [DL]

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

stdin

821 122
341 164
245 715
317 267
414 119
972 896
799 994
844 528
817 554
498 988
323 423
471 779
977 762
911 145
977 114
754 449
566 117
718 815
944 199
611 119
966 363
359 598
635 772
473 239
877 371
644 346
991 169
795 491
547 774
824 236
889 821
985 958

stdout

stderr

[/volume/CODE line 4] Error at '}': Expect newline after statement.
[/volume/CODE line 4] Error at end of file: Expect '}' at end of block.

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffd548cdcd0 /* 9 vars */) = 0
12    execve("/root/wren", ["/root/wren", "/volume/CODE"], 0x55bae36b3d40 /* 9 vars */) = 0
12    +++ exited with 65 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=65, si_utime=0, si_stime=0} ---
11    execve("/bin/cat", ["cat", "-"], 0x55bae36b3d30 /* 9 vars */) = 0
11    --- SIGPIPE {si_signo=SIGPIPE, si_code=SI_USER, si_pid=11, si_uid=0} ---
11    +++ killed by SIGPIPE +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_KILLED, si_pid=11, si_uid=0, si_status=SIGPIPE, si_utime=0, si_stime=0} ---
10    +++ exited with 65 +++