php, 50 bytes

Result

WA

Duration

769ms

Code [DL]

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

stdin

133 731
763 615
187 789
449 484
227 374
828 772
327 622
618 668
766 733
846 439
218 181
499 771
629 995
577 415
338 853
566 993
285 223
167 264
414 413
383 889
313 132
962 669
656 417
496 546
711 125
955 537
766 663
466 263
499 991
363 337
151 615
537 753

stdout

76743766741794892248164515629367

stderr

strace

11    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc0c896de0 /* 7 vars */) = 0
13    execve("/usr/bin/php", ["/usr/bin/php", "/volume/CODE"], 0x55cf54f54d40 /* 7 vars */ <unfinished ...>
12    execve("/bin/cat", ["cat", "-"], 0x55cf54f54d30 /* 7 vars */ <unfinished ...>
13    <... execve resumed>)             = 0
12    <... execve resumed>)             = 0
12    +++ exited with 0 +++
11    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
13    +++ exited with 0 +++
11    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
11    +++ exited with 0 +++