php, 47 bytes

Result

WA

Duration

789ms

Code [DL]

<? while($_=readline())echo$_[$_[1]-$_[2]?4:2];

stdin

245 457
752 447
271 779
747 359
667 761
211 118
248 981
635 557
954 536
798 412
745 752
322 772
968 882
344 845
626 642
732 433
774 471
941 924
411 527
199 431
588 245
287 898
826 992
288 287
767 716
655 448
269 663
296 965
272 975
766 665
911 122
877 733

stdout

<? while($_=readline())echo$_[$_[1]-$_[2]?4:2];

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffddee4c390 /* 7 vars */) = 0
12    execve("/usr/bin/php", ["/usr/bin/php", "/volume/CODE"], 0x55d0ee156d40 /* 7 vars */ <unfinished ...>
11    execve("/bin/cat", ["cat", "-"], 0x55d0ee156d30 /* 7 vars */ <unfinished ...>
12    <... execve resumed>)             = 0
11    <... 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 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 +++