lua, 50 bytes

Result

WA

Duration

766ms

Code [DL]

repeat until print(io.read():match("(.) ?%1")or 1)

stdin

334 433
668 867
827 278
938 443
785 551
593 372
676 731
577 742
667 875
655 746
269 797
477 278
311 142
812 113
114 112
663 637
188 926
785 559
224 326
533 343
911 773
624 161
114 488
166 991
973 711
929 971
511 117
984 566
581 447
234 631
455 151
766 668

stdout

3
6
1
4
5
3
1
7
6
5
1
7
1
1
1
6
8
5
2
3
1
1
1
6
1
9
1
6
4
1
5
6

stderr

/usr/bin/lua5.3: /volume/CODE:1: attempt to index a nil value
stack traceback:
	/volume/CODE:1: in main chunk
	[C]: in ?

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffe6d4135f0 /* 7 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x55d45e796d30 /* 7 vars */) = 0
12    execve("/usr/bin/lua5.3", ["/usr/bin/lua5.3", "/volume/CODE"], 0x55d45e796d40 /* 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    +++ 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 +++