reasonml, 195 bytes

Result

WA

Duration

1072ms

Code [DL]

for (i in 0 to 31) {
  let a = Node.Fs.readFileSync("/dev/stdin", `utf8);
  if (a.[1] == a.[2]) {
    print_string(String.sub(a, 2, 2));
  } else {
    print_string(String.sub(a, 4, 4));
  };
};

stdin

231 113
693 386
874 679
314 392
242 247
522 884
116 118
338 882
811 112
949 897
548 484
278 872
577 577
289 612
755 577
421 716
134 993
866 664
899 116
849 495
283 884
238 529
963 615
233 827
443 224
855 763
822 285
612 828
981 155
235 836
561 647
988 982

stdout

stderr

  Warning number 35
  /tmp/code.re 1:1-8:1
  
  1 │ for (i in 0 to 31) {
  2 │   let a = Node.Fs.readFileSync("/dev/stdin", `utf8);
  . │ ...
  7 │   };
  8 │ };
  
  unused for-loop index i.
  internal/modules/cjs/loader.js:983
  throw err;
  ^

Error: Cannot find module 'bs-platform/lib/js/string.js'
Require stack:
- /tmp/code.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:980:15)
    at Function.Module._load (internal/modules/cjs/loader.js:862:27)
    at Module.require (internal/modules/cjs/loader.js:1042:19)
    at require (internal/modules/cjs/helpers.js:77:18)
    at Object.<anonymous> (/tmp/code.js:5:16)
    at Module._compile (internal/modules/cjs/loader.js:1156:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1176:10)
    at Module.load (internal/modules/cjs/loader.js:1000:32)
    at Function.Module._load (internal/modules/cjs/loader.js:899:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ '/tmp/code.js' ]
}

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc61c24e70 /* 9 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55e875e56d18 /* 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    execve("/bin/ln", ["ln", "-sf", "/volume/CODE", "/tmp/code.re"], 0x55e875e56d38 /* 9 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("/usr/bin/bsc", ["/usr/bin/bsc", "/tmp/code.re"], 0x55e875e56d20 /* 9 vars */) = 0
13    execve("/bin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fff48091cc0 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/local/sbin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fff48091cc0 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/local/bin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fff48091cc0 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/sbin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fff48091cc0 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/bin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fff48091cc0 /* 9 vars */) = 0
20    execve("/usr/lib/node_modules/bs-platform/linux/bsc.exe", ["/usr/lib/node_modules/bs-platfor"..., "/tmp/code.re"], 0x5615036d3640 /* 9 vars */) = 0
21    execve("/bin/sh", ["sh", "-c", "/usr/lib/node_modules/bs-platfor"...], 0x7ffd732a8c60 /* 9 vars */) = 0
21    execve("/usr/lib/node_modules/bs-platform/linux/refmt.exe", ["/usr/lib/node_modules/bs-platfor"..., "--print=binary", "/tmp/code.re"], 0x560f11d05090 /* 9 vars */) = 0
21    +++ exited with 0 +++
20    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
20    +++ exited with 0 +++
13    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=20, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
18    +++ exited with 0 +++
17    +++ exited with 0 +++
16    +++ exited with 0 +++
15    +++ exited with 0 +++
14    +++ exited with 0 +++
19    +++ exited with 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=4, si_stime=1} ---
22    execve("/bin/cat", ["cat", "-"], 0x55e875e56d38 /* 9 vars */ <unfinished ...>
23    execve("/usr/bin/node", ["/usr/bin/node", "/tmp/code.js"], 0x55e875e56d48 /* 9 vars */ <unfinished ...>
22    <... execve resumed>)             = 0
23    <... execve resumed>)             = 0
22    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=22, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
27    +++ exited with 0 +++
28    +++ exited with 0 +++
26    +++ exited with 0 +++
25    +++ exited with 0 +++
24    +++ exited with 0 +++
29    +++ exited with 1 +++
23    +++ exited with 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=23, si_uid=0, si_status=1, si_utime=2, si_stime=1} ---
30    execve("/bin/rm", ["rm", "/tmp/code.js", "/tmp/code.re"], 0x55e875e56cf0 /* 9 vars */) = 0
30    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=30, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++