lua, 118 bytes

Result

AC

Duration

767ms

Code [DL]

while true do
a,b=io.read("*n","*n")
if a%10==(a%100-a%10)/10
then io.write(a%10)
else io.write((b-b%100)/100)
end
end

stdin

483 311
493 993
718 449
238 369
191 841
435 752
199 443
288 531
874 443
798 831
795 351
811 454
329 425
917 832
133 334
634 933
199 889
766 655
775 817
755 758
354 554
134 392
796 975
317 175
678 784
399 994
123 336
389 117
711 153
771 178
532 235
566 969

stdout

39438798483148399685539179311126

stderr

/usr/bin/lua5.3: /volume/CODE:3: attempt to perform arithmetic on a nil value (global 'a')
stack traceback:
	/volume/CODE:3: in main chunk
	[C]: in ?

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffed75ebe00 /* 7 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x564ff2eaad30 /* 7 vars */ <unfinished ...>
12    execve("/usr/bin/lua5.3", ["/usr/bin/lua5.3", "/volume/CODE"], 0x564ff2eaad40 /* 7 vars */ <unfinished ...>
11    <... execve resumed>)             = 0
12    <... 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 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=1, si_utime=0, si_stime=0} ---
10    +++ exited with 1 +++