php, 50 bytes

Result

AC

Duration

1154ms

Code [DL]

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

stdin

411 775
782 557
226 263
699 773
553 332
299 657
928 889
922 221
522 219
211 114
711 569
466 764
428 558
145 742
521 414
946 546
861 519
731 125
524 434
936 317
313 857
212 123
237 734
313 117
471 476
491 995
352 259
327 148
271 774
499 956
916 172
544 245

stdout

15293982211657455143817149217914

stderr

strace

12    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7fffc15ef030 /* 7 vars */) = 0
14    execve("/usr/bin/php", ["/usr/bin/php", "/volume/CODE"], 0x5559e52aed40 /* 7 vars */) = 0
13    execve("/bin/cat", ["cat", "-"], 0x5559e52aed30 /* 7 vars */) = 0
13    +++ exited with 0 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
14    +++ exited with 0 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
12    +++ exited with 0 +++