oh, 85 bytes

Result

AC

Duration

928ms

Code [DL]

while 1:(method(a b c d e:g)=:if(eq $b $c)(echo $c)else:echo $e)@(""::split:readline)

stdin

351 381
166 635
138 918
716 165
755 678
479 959
135 614
967 761
373 376
557 593
544 441
387 886
412 929
297 772
766 513
944 416
696 166
144 145
388 982
592 998
475 583
113 332
135 833
241 348
864 881
922 663
661 643
955 553
499 775
167 557
937 375
728 389

stdout

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

stderr

boot.oh: 360: error/runtime: argument 1 (of 1) is invalid

strace

11    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc5074bf00 /* 7 vars */) = 0
12    execve("/bin/cat", ["cat", "-"], 0x56050cef2048 /* 7 vars */) = 0
14    execve("/usr/bin/go", ["/usr/bin/go", "env", "GOPATH"], 0x56050cef2078 /* 7 vars */) = 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} ---
16    +++ exited with 0 +++
17    +++ exited with 0 +++
19    +++ exited with 0 +++
15    +++ exited with 0 +++
18    +++ exited with 0 +++
14    +++ exited with 0 +++
13    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
13    execve("/root/go/bin/oh", ["/root/go/bin/oh", "/volume/CODE"], 0x56050cef2068 /* 7 vars */) = 0
26    +++ exited with 0 +++
24    +++ exited with 0 +++
20    +++ exited with 0 +++
25    +++ exited with 0 +++
21    +++ exited with 0 +++
23    +++ exited with 0 +++
22    +++ exited with 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=3, si_stime=6} ---
11    +++ exited with 0 +++