golang, 99 bytes

Result

WA

Duration

1619ms

Code [DL]

package main
import."fmt"
func main(){for{a,b:=0,0;Scan(&a,&b);if 0/a+b%110<9{a=b/10};Print(a%10)}}

stdin

981 626
422 665
983 773
418 886
614 442
784 821
155 528
146 649
251 283
869 296
177 622
862 261
611 599
153 386
526 268
275 229
822 424
172 725
788 886
317 818
266 226
277 172
143 482
434 338
612 376
977 731
324 525
875 899
387 743
372 778
477 779
681 915

stdout

16784456197213652287273327457771

stderr

panic: runtime error: integer divide by zero

goroutine 1 [running]:
main.main()
	/tmp/code.go:3 +0x1f1

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffe4da5b5d0 /* 7 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55c652100d18 /* 7 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.go"], 0x55c652100d38 /* 7 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/go", ["/usr/bin/go", "build", "-o", "/tmp/code", "/tmp/code.go"], 0x55c6533f7028 /* 7 vars */) = 0
20    execve("/usr/lib/go/pkg/tool/linux_amd64/compile", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-V=full"], 0xc000133790 /* 25 vars */) = 0
21    execve("/usr/lib/go/pkg/tool/linux_amd64/compile", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-V=full"], 0xc000291ee0 /* 25 vars */) = 0
24    +++ exited with 0 +++
25    +++ exited with 0 +++
23    +++ exited with 0 +++
20    +++ exited with 0 +++
14    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=20, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
28    +++ exited with 0 +++
29    +++ exited with 0 +++
27    +++ exited with 0 +++
21    +++ exited with 0 +++
18    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
26    execve("/usr/lib/go/pkg/tool/linux_amd64/asm", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-V=full"], 0xc00015e0d0 /* 25 vars */) = 0
30    execve("/usr/lib/go/pkg/tool/linux_amd64/asm", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-V=full"], 0xc000133a00 /* 25 vars */) = 0
37    ????( <unfinished ...>
32    +++ exited with 0 +++
31    +++ exited with 0 +++
34    +++ exited with 0 +++
37    +++ exited with 0 +++
26    +++ exited with 0 +++
19    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=26, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
35    +++ exited with 0 +++
36    +++ exited with 0 +++
33    +++ exited with 0 +++
38    +++ exited with 0 +++
30    +++ exited with 0 +++
14    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=30, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
39    execve("/usr/lib/go/pkg/tool/linux_amd64/compile", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-o", "/tmp/go-build450861481/b001/_pkg"..., "-trimpath", "/tmp/go-build450861481/b001=>", "-p", "main", "-complete", "-buildid", "Gfw6dZvnLtVyR98vltuj/Gfw6dZvnLtV"..., "-goversion", "go1.13.10", "-D", "_/tmp", "-importcfg", "/tmp/go-build450861481/b001/impo"..., "-pack", "-c=2", "/tmp/code.go"], 0xc0004504e0 /* 25 vars */) = 0
43    +++ exited with 0 +++
42    +++ exited with 0 +++
41    +++ exited with 0 +++
40    +++ exited with 0 +++
39    +++ exited with 0 +++
18    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=39, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
44    execve("/usr/lib/go/pkg/tool/linux_amd64/link", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-V=full"], 0xc000450820 /* 25 vars */) = 0
47    +++ exited with 0 +++
45    +++ exited with 0 +++
48    +++ exited with 0 +++
46    +++ exited with 0 +++
44    +++ exited with 0 +++
22    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=44, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
49    execve("/usr/lib/go/pkg/tool/linux_amd64/link", ["/usr/lib/go/pkg/tool/linux_amd64"..., "-o", "/tmp/go-build450861481/b001/exe/"..., "-importcfg", "/tmp/go-build450861481/b001/impo"..., "-buildmode=exe", "-buildid=DAggzhCmRqpsFQUd6wRD/Gf"..., "-extld=gcc", "/tmp/go-build450861481/b001/_pkg"...], 0xc000450c30 /* 25 vars */) = 0
50    +++ exited with 0 +++
53    +++ exited with 0 +++
52    +++ exited with 0 +++
51    +++ exited with 0 +++
49    +++ exited with 0 +++
22    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=49, si_uid=0, si_status=0, si_utime=18, si_stime=3} ---
22    +++ exited with 0 +++
19    +++ exited with 0 +++
18    +++ exited with 0 +++
17    +++ exited with 0 +++
15    +++ exited with 0 +++
14    +++ exited with 0 +++
16    +++ 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=6, si_stime=17} ---
54    execve("/bin/cat", ["cat", "-"], 0x55c652100d08 /* 7 vars */) = 0
55    execve("/tmp/code", ["/tmp/code"], 0x55c652100cf0 /* 7 vars */) = 0
54    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=54, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
59    +++ exited with 2 +++
58    +++ exited with 2 +++
57    +++ exited with 2 +++
56    +++ exited with 2 +++
55    +++ exited with 2 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=55, si_uid=0, si_status=2, si_utime=0, si_stime=1} ---
60    execve("/bin/rm", ["rm", "/tmp/code.go", "/tmp/code"], 0x55c652100cf0 /* 7 vars */) = 0
60    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=60, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++